diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..050a900
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,49 @@
+# Changelog
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+### Added
+ - VANISHED support in EXPUNGE responses and unsolicited responses (#172).
+
+### Changed
+ - MSRV increased to 1.43 for nom6 and bitvec
+ - `expunge` and `uid_expunge` return `Result<Deleted>` instead of `Result<Vec<u32>>`.
+
+### Removed
+
+## [2.4.1] - 2021-01-12
+### Changed
+
+ - Handle empty-set inputs to `fetch` and `uid_fetch` (#177)
+
+## [2.4.0] - 2020-12-15
+### Added
+
+ - `append_with_flags_and_date` (#174)
+
+## [2.3.0] - 2020-08-23
+### Added
+
+ - `append_with_flags` (#171)
+
+## [2.2.0] - 2020-07-27
+### Added
+
+ - Changelog
+ - STARTTLS example (#165)
+ - Timeout example (#168)
+ - Export `Result` and `Error` types (#170)
+
+### Changed
+
+ - MSRV increased
+ - Better documentation of server greeting handling (#168)
+
+[Unreleased]: https://github.com/jonhoo/rust-imap/compare/v2.4.1...HEAD
+[2.4.1]: https://github.com/jonhoo/rust-imap/compare/v2.4.0...v2.4.1
+[2.4.0]: https://github.com/jonhoo/rust-imap/compare/v2.3.0...v2.4.0
+[2.3.0]: https://github.com/jonhoo/rust-imap/compare/v2.2.0...v2.3.0
+[2.2.0]: https://github.com/jonhoo/rust-imap/compare/v2.1.2...v2.2.0
diff --git a/Cargo.toml b/Cargo.toml
index d7172e4..3b1a975 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,26 +1,18 @@
 [package]
 name = "imap"
-version = "2.1.2"
-authors = ["Matt McCoy <mattnenterprise@yahoo.com>",
-           "Jon Gjengset <jon@thesquareplanet.com>"]
+version = "3.0.0-alpha.1"
+authors = ["Jon Gjengset <jon@thesquareplanet.com>",
+           "Matt McCoy <mattnenterprise@yahoo.com>"]
 documentation = "https://docs.rs/imap/"
 repository = "https://github.com/jonhoo/rust-imap"
 homepage = "https://github.com/jonhoo/rust-imap"
 description = "IMAP client for Rust"
-readme = "README.md"
-license = "Apache-2.0/MIT"
+license = "Apache-2.0 OR MIT"
 edition = "2018"
 
 keywords = ["email", "imap"]
 categories = ["email", "network-programming"]
 
-[badges]
-azure-devops = { project = "jonhoo/jonhoo", pipeline = "imap", build = "11" }
-codecov = { repository = "jonhoo/rust-imap", branch = "master", service = "github" }
-maintenance = { status = "actively-developed" }
-is-it-maintained-issue-resolution = { repository = "jonhoo/rust-imap" }
-is-it-maintained-open-issues = { repository = "jonhoo/rust-imap" }
-
 [features]
 tls = ["native-tls"]
 default = ["tls"]
@@ -29,16 +21,16 @@ default = ["tls"]
 native-tls = { version = "0.2.2", optional = true }
 regex = "1.0"
 bufstream = "0.1"
-imap-proto = "0.10.0"
-nom = "5.0"
-base64 = "0.12"
+imap-proto = "0.12.0"
+nom = "6.0"
+base64 = "0.13"
 chrono = "0.4"
 lazy_static = "1.4"
 
 [dev-dependencies]
 lettre = "0.9"
 lettre_email = "0.9"
-rustls-connector = "0.11.0"
+rustls-connector = "0.13.0"
 
 [[example]]
 name = "basic"
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index 5cc11d8..aa6917d 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -25,9 +25,6 @@ jobs:
      - template: install-rust.yml@templates
        parameters:
          rust: $(rust)
-         components:
-           - rustfmt
-           - clippy
      - script: cargo check --all-targets
        displayName: cargo check
      - script: cargo test --examples
@@ -36,10 +33,16 @@ jobs:
        displayName: cargo test --doc
      - script: cargo test --lib
        displayName: cargo test --lib
-     - script: cargo fmt --all -- --check
+     - script: |
+         set -e
+         rustup component add rustfmt
+         cargo fmt --all -- --check
        displayName: cargo fmt --check
        condition: and(eq( variables['rust'], 'beta' ), eq( variables['Agent.OS'], 'Linux' ))
-     - script: cargo clippy -- -D warnings
+     - script: |
+         set -e
+         rustup component add clippy
+         cargo clippy -- -D warnings
        displayName: cargo clippy
        condition: and(eq( variables['rust'], 'beta' ), eq( variables['Agent.OS'], 'Linux' ))
  # This represents the minimum Rust version supported.
@@ -47,12 +50,12 @@ jobs:
  - job: msrv
    pool:
      vmImage: ubuntu-latest
-   displayName: "Minimum supported Rust version: 1.36.0"
+   displayName: "Minimum supported Rust version: 1.43.0"
    dependsOn: []
    steps:
      - template: install-rust.yml@templates
        parameters:
-         rust: 1.36.0
+         rust: 1.43.0 # nom6 depends on bitvec (1.43+)
      - script: cargo check
        displayName: cargo check
  - job: integration
@@ -79,11 +82,11 @@ resources:
     - repository: templates
       type: github
       name: crate-ci/azure-pipelines
-      ref: refs/heads/v0.3
+      ref: refs/heads/v0.4
       endpoint: jonhoo
   containers:
    - container: greenmail
-     image: greenmail/standalone:1.5.11
+     image: greenmail/standalone:1.5.13
      ports:
        - 3025:3025
        - 3110:3110
diff --git a/examples/README.md b/examples/README.md
index b1bde9d..1ba24a0 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -7,3 +7,4 @@ Examples:
   * basic - This is a very basic example of using the client.
   * gmail_oauth2 - This is an example using oauth2 for logging into gmail as a secure appplication.
   * rustls - This demonstrates how to use Rustls instead of Openssl for secure connections (helpful for cross compilation).
+  * timeout - This demonstrates how to use timeouts while connecting to an IMAP server.
diff --git a/examples/starttls.rs b/examples/starttls.rs
new file mode 100644
index 0000000..071021f
--- /dev/null
+++ b/examples/starttls.rs
@@ -0,0 +1,63 @@
+/**
+ * Here's an example showing how to connect to the IMAP server with STARTTLS.
+ * The only difference with the `basic.rs` example is when using `imap::connect_starttls()` method
+ * instead of `imap::connect()` (l. 52), and so you can connect on port 143 instead of 993
+ * as you have to when using TLS the entire way.
+ *
+ * The following env vars are expected to be set:
+ * - IMAP_HOST
+ * - IMAP_USERNAME
+ * - IMAP_PASSWORD
+ * - IMAP_PORT (supposed to be 143)
+ */
+extern crate imap;
+extern crate native_tls;
+
+use native_tls::TlsConnector;
+use std::env;
+use std::error::Error;
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let imap_host = env::var("IMAP_HOST").expect("Missing or invalid env var: IMAP_HOST");
+    let imap_username =
+        env::var("IMAP_USERNAME").expect("Missing or invalid env var: IMAP_USERNAME");
+    let imap_password =
+        env::var("IMAP_PASSWORD").expect("Missing or invalid env var: IMAP_PASSWORD");
+    let imap_port: u16 = env::var("IMAP_PORT")
+        .expect("Missing or invalid env var: IMAP_PORT")
+        .to_string()
+        .parse()
+        .unwrap();
+
+    if let Some(_email) = fetch_inbox_top(imap_host, imap_username, imap_password, imap_port)? {
+        eprintln!("OK :)");
+    }
+
+    Ok(())
+}
+
+fn fetch_inbox_top(
+    host: String,
+    username: String,
+    password: String,
+    port: u16,
+) -> Result<Option<String>, Box<dyn Error>> {
+    let domain: &str = host.as_str();
+
+    let tls = TlsConnector::builder().build().unwrap();
+
+    // we pass in the domain twice to check that the server's TLS
+    // certificate is valid for the domain we're connecting to.
+    let client = imap::connect_starttls((domain, port), domain, &tls).unwrap();
+
+    // the client we have here is unauthenticated.
+    // to do anything useful with the e-mails, we need to log in
+    let mut _imap_session = client
+        .login(username.as_str(), password.as_str())
+        .map_err(|e| e.0)?;
+
+    // TODO Here you can process as you want. eg. search/fetch messages according to your needs.
+
+    // This returns `Ok(None)` for the need of the example
+    Ok(None)
+}
diff --git a/examples/timeout.rs b/examples/timeout.rs
new file mode 100644
index 0000000..d2d717e
--- /dev/null
+++ b/examples/timeout.rs
@@ -0,0 +1,92 @@
+extern crate imap;
+extern crate native_tls;
+
+use imap::Client;
+use native_tls::TlsConnector;
+use native_tls::TlsStream;
+use std::env;
+use std::error::Error;
+use std::fmt;
+use std::net::{SocketAddr, TcpStream, ToSocketAddrs};
+use std::time::Duration;
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let server = env::var("IMAP_SERVER")?;
+    let port = env::var("IMAP_PORT").unwrap_or_else(|_| String::from("993"));
+    let port = port.parse()?;
+
+    let username = env::var("IMAP_USER")?;
+    let password = env::var("IMAP_PASSWORD")?;
+
+    let timeout = env::var("IMAP_TIMEOUT").unwrap_or_else(|_| String::from("1"));
+    let timeout = timeout.parse()?;
+    let timeout = Duration::from_secs(timeout);
+
+    let tls = TlsConnector::builder().build()?;
+
+    let client = connect_all_timeout((server.as_str(), port), server.as_str(), &tls, timeout)?;
+
+    let mut session = client.login(&username, &password).map_err(|e| e.0)?;
+
+    // do something productive with session
+
+    session.logout()?;
+
+    Ok(())
+}
+
+// connect to an IMAP host with a `Duration` timeout; note that this accepts only a single
+// `SocketAddr` while `connect_all_timeout` does resolve the DNS entry and try to connect to all;
+// this is necessary due to the difference of the function signatures of `TcpStream::connect` and
+// `TcpStream::connect_timeout`
+fn connect_timeout<S: AsRef<str>>(
+    addr: &SocketAddr,
+    domain: S,
+    ssl_connector: &TlsConnector,
+    timeout: Duration,
+) -> Result<Client<TlsStream<TcpStream>>, Box<dyn Error>> {
+    // the timeout is actually used with the initial TcpStream
+    let tcp_stream = TcpStream::connect_timeout(addr, timeout)?;
+
+    let tls_stream = TlsConnector::connect(ssl_connector, domain.as_ref(), tcp_stream)?;
+
+    let mut client = Client::new(tls_stream);
+
+    // don't forget to wait for the IMAP protocol server greeting ;)
+    client.read_greeting()?;
+
+    Ok(client)
+}
+
+// resolve address and try to connect to all in order; note that this function is required to fully
+// mimic `imap::connect` with the usage of `ToSocketAddrs`
+fn connect_all_timeout<A: ToSocketAddrs, S: AsRef<str>>(
+    addr: A,
+    domain: S,
+    ssl_connector: &TlsConnector,
+    timeout: Duration,
+) -> Result<Client<TlsStream<TcpStream>>, Box<dyn Error>> {
+    let addrs = addr.to_socket_addrs()?;
+
+    for addr in addrs {
+        match connect_timeout(&addr, &domain, ssl_connector, timeout) {
+            Ok(client) => return Ok(client),
+            Err(error) => eprintln!("couldn't connect to {}: {}", addr, error),
+        }
+    }
+
+    Err(Box::new(TimeoutError))
+}
+
+// very simple timeout error; instead of printing the errors immediately like in
+// `connect_all_timeout`, you may want to collect and return them
+#[derive(Debug)]
+struct TimeoutError;
+
+impl fmt::Display for TimeoutError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "all addresses failed to connect")
+    }
+}
+
+impl Error for TimeoutError {}
diff --git a/src/client.rs b/src/client.rs
index e053466..d3a9e0e 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -1,8 +1,7 @@
-use base64;
 use bufstream::BufStream;
+use chrono::{DateTime, FixedOffset};
 #[cfg(feature = "tls")]
 use native_tls::{TlsConnector, TlsStream};
-use nom;
 use std::collections::HashSet;
 use std::io::{Read, Write};
 use std::net::{TcpStream, ToSocketAddrs};
@@ -27,15 +26,74 @@ macro_rules! quote {
     };
 }
 
+trait OptionExt<E> {
+    fn err(self) -> std::result::Result<(), E>;
+}
+
+impl<E> OptionExt<E> for Option<E> {
+    fn err(self) -> std::result::Result<(), E> {
+        match self {
+            Some(e) => Err(e),
+            None => Ok(()),
+        }
+    }
+}
+
+/// Convert the input into what [the IMAP
+/// grammar](https://tools.ietf.org/html/rfc3501#section-9)
+/// calls "quoted", which is reachable from "string" et al.
+/// Also ensure it doesn't contain a colliding command-delimiter (newline).
 pub(crate) fn validate_str(value: &str) -> Result<String> {
-    let quoted = quote!(value);
-    if quoted.find('\n').is_some() {
-        return Err(Error::Validate(ValidateError('\n')));
-    }
-    if quoted.find('\r').is_some() {
-        return Err(Error::Validate(ValidateError('\r')));
-    }
-    Ok(quoted)
+    validate_str_noquote(value)?;
+    Ok(quote!(value))
+}
+
+/// Ensure the input doesn't contain a command-terminator (newline), but don't quote it like
+/// `validate_str`.
+/// This is helpful for things like the FETCH attributes, which,
+/// per [the IMAP grammar](https://tools.ietf.org/html/rfc3501#section-9) may not be quoted:
+///
+/// > fetch     = "FETCH" SP sequence-set SP ("ALL" / "FULL" / "FAST" /
+/// >             fetch-att / "(" fetch-att *(SP fetch-att) ")")
+/// >
+/// > fetch-att = "ENVELOPE" / "FLAGS" / "INTERNALDATE" /
+/// >             "RFC822" [".HEADER" / ".SIZE" / ".TEXT"] /
+/// >             "BODY" ["STRUCTURE"] / "UID" /
+/// >             "BODY" section ["<" number "." nz-number ">"] /
+/// >             "BODY.PEEK" section ["<" number "." nz-number ">"]
+///
+/// Note the lack of reference to any of the string-like rules or the quote characters themselves.
+fn validate_str_noquote(value: &str) -> Result<&str> {
+    value
+        .matches(|c| c == '\n' || c == '\r')
+        .next()
+        .and_then(|s| s.chars().next())
+        .map(|offender| Error::Validate(ValidateError(offender)))
+        .err()?;
+    Ok(value)
+}
+
+/// This ensures the input doesn't contain a command-terminator or any other whitespace
+/// while leaving it not-quoted.
+/// This is needed because, per [the formal grammer given in RFC
+/// 3501](https://tools.ietf.org/html/rfc3501#section-9), a sequence set consists of the following:
+///
+/// > sequence-set = (seq-number / seq-range) *("," sequence-set)
+/// > seq-range = seq-number ":" seq-number
+/// > seq-number = nz-number / "*"
+/// > nz-number       = digit-nz *DIGIT
+/// > digit-nz        = %x31-39
+///
+/// Note the lack of reference to SP or any other such whitespace terminals.
+/// Per this grammar, in theory we ought to be even more restrictive than "no whitespace".
+fn validate_sequence_set(value: &str) -> Result<&str> {
+    value
+        .matches(|c: char| c.is_ascii_whitespace())
+        .next()
+        .and_then(|s| s.chars().next())
+        .map(|offender| Error::Validate(ValidateError(offender)))
+        .err()?;
+    Ok(value)
 }
 
 /// An authenticated IMAP session providing the usual IMAP commands. This type is what you get from
@@ -83,6 +141,87 @@ pub struct Connection<T: Read + Write> {
     pub greeting_read: bool,
 }
 
+/// A builder for the append command
+#[must_use]
+pub struct AppendCmd<'a, T: Read + Write> {
+    session: &'a mut Session<T>,
+    content: &'a [u8],
+    mailbox: &'a str,
+    flags: Vec<Flag<'a>>,
+    date: Option<DateTime<FixedOffset>>,
+}
+
+impl<'a, T: Read + Write> AppendCmd<'a, T> {
+    /// The [`APPEND` command](https://tools.ietf.org/html/rfc3501#section-6.3.11) can take
+    /// an optional FLAGS parameter to set the flags on the new message.
+    ///
+    /// > If a flag parenthesized list is specified, the flags SHOULD be set
+    /// > in the resulting message; otherwise, the flag list of the
+    /// > resulting message is set to empty by default.  In either case, the
+    /// > Recent flag is also set.
+    ///
+    /// The [`\Recent` flag](https://tools.ietf.org/html/rfc3501#section-2.3.2) is not
+    /// allowed as an argument to `APPEND` and will be filtered out if present in `flags`.
+    pub fn flag(&mut self, flag: Flag<'a>) -> &mut Self {
+        self.flags.push(flag);
+        self
+    }
+
+    /// Set multiple flags at once.
+    pub fn flags(&mut self, flags: impl IntoIterator<Item = Flag<'a>>) -> &mut Self {
+        self.flags.extend(flags);
+        self
+    }
+
+    /// Pass a date in order to set the date that the message was originally sent.
+    ///
+    /// > If a date-time is specified, the internal date SHOULD be set in
+    /// > the resulting message; otherwise, the internal date of the
+    /// > resulting message is set to the current date and time by default.
+    pub fn internal_date(&mut self, date: DateTime<FixedOffset>) -> &mut Self {
+        self.date = Some(date);
+        self
+    }
+
+    /// Finishes up the command and executes it.
+    ///
+    /// Note: be sure to set flags and optional date before you
+    /// finish the command.
+    pub fn finish(&mut self) -> Result<()> {
+        let flagstr = self
+            .flags
+            .clone()
+            .into_iter()
+            .filter(|f| *f != Flag::Recent)
+            .map(|f| f.to_string())
+            .collect::<Vec<String>>()
+            .join(" ");
+
+        let datestr = if let Some(date) = self.date {
+            format!(" \"{}\"", date.format("%d-%h-%Y %T %z"))
+        } else {
+            "".to_string()
+        };
+
+        self.session.run_command(&format!(
+            "APPEND \"{}\" ({}){} {{{}}}",
+            self.mailbox,
+            flagstr,
+            datestr,
+            self.content.len()
+        ))?;
+        let mut v = Vec::new();
+        self.session.readline(&mut v)?;
+        if !v.starts_with(b"+") {
+            return Err(Error::Append);
+        }
+        self.session.stream.write_all(self.content)?;
+        self.session.stream.write_all(b"\r\n")?;
+        self.session.stream.flush()?;
+        self.session.read_response().map(|_| ())
+    }
+}
+
 // `Deref` instances are so we can make use of the same underlying primitives in `Client` and
 // `Session`
 impl<T: Read + Write> Deref for Client<T> {
@@ -240,6 +379,29 @@ impl<T: Read + Write> Client<T> {
     ///
     /// This method primarily exists for writing tests that mock the underlying transport, but can
     /// also be used to support IMAP over custom tunnels.
+    ///
+    /// **Note:** In case you do need to use `Client::new` over `imap::connect`, you will need to
+    /// listen for the IMAP protocol server greeting before authenticating:
+    ///
+    /// ```rust,no_run
+    /// # extern crate imap;
+    /// # extern crate native_tls;
+    /// # use imap::Client;
+    /// # use native_tls::TlsConnector;
+    /// # use std::io;
+    /// # use std::net::TcpStream;
+    /// # fn main() {
+    /// # let server = "imap.example.com";
+    /// # let username = "";
+    /// # let password = "";
+    /// # let tcp = TcpStream::connect((server, 993)).unwrap();
+    /// # let ssl_connector = TlsConnector::builder().build().unwrap();
+    /// # let tls = TlsConnector::connect(&ssl_connector, server.as_ref(), tcp).unwrap();
+    /// let mut client = Client::new(tls);
+    /// client.read_greeting().unwrap();
+    /// let session = client.login(username, password).unwrap();
+    /// # }
+    /// ```
     pub fn new(stream: T) -> Client<T> {
         Client {
             conn: Connection {
@@ -456,7 +618,7 @@ impl<T: Read + Write> Session<T> {
         .and_then(|lines| parse_mailbox(&lines[..], &mut self.unsolicited_responses_tx))
     }
 
-    /// Fetch retreives data associated with a set of messages in the mailbox.
+    /// Fetch retrieves data associated with a set of messages in the mailbox.
     ///
     /// Note that the server *is* allowed to unilaterally include `FETCH` responses for other
     /// messages in the selected mailbox whose status has changed. See the note on [unilateral
@@ -519,12 +681,16 @@ impl<T: Read + Write> Session<T> {
         S1: AsRef<str>,
         S2: AsRef<str>,
     {
-        self.run_command_and_read_response(&format!(
-            "FETCH {} {}",
-            sequence_set.as_ref(),
-            query.as_ref()
-        ))
-        .and_then(|lines| parse_fetches(lines, &mut self.unsolicited_responses_tx))
+        if sequence_set.as_ref().is_empty() {
+            parse_fetches(vec![], &mut self.unsolicited_responses_tx)
+        } else {
+            self.run_command_and_read_response(&format!(
+                "FETCH {} {}",
+                validate_sequence_set(sequence_set.as_ref())?,
+                validate_str_noquote(query.as_ref())?
+            ))
+            .and_then(|lines| parse_fetches(lines, &mut self.unsolicited_responses_tx))
+        }
     }
 
     /// Equivalent to [`Session::fetch`], except that all identifiers in `uid_set` are
@@ -534,12 +700,16 @@ impl<T: Read + Write> Session<T> {
         S1: AsRef<str>,
         S2: AsRef<str>,
     {
-        self.run_command_and_read_response(&format!(
-            "UID FETCH {} {}",
-            uid_set.as_ref(),
-            query.as_ref()
-        ))
-        .and_then(|lines| parse_fetches(lines, &mut self.unsolicited_responses_tx))
+        if uid_set.as_ref().is_empty() {
+            parse_fetches(vec![], &mut self.unsolicited_responses_tx)
+        } else {
+            self.run_command_and_read_response(&format!(
+                "UID FETCH {} {}",
+                validate_sequence_set(uid_set.as_ref())?,
+                validate_str_noquote(query.as_ref())?
+            ))
+            .and_then(|lines| parse_fetches(lines, &mut self.unsolicited_responses_tx))
+        }
     }
 
     /// Noop always succeeds, and it does nothing.
@@ -666,7 +836,7 @@ impl<T: Read + Write> Session<T> {
     /// The [`EXPUNGE` command](https://tools.ietf.org/html/rfc3501#section-6.4.3) permanently
     /// removes all messages that have [`Flag::Deleted`] set from the currently selected mailbox.
     /// The message sequence number of each message that is removed is returned.
-    pub fn expunge(&mut self) -> Result<Vec<Seq>> {
+    pub fn expunge(&mut self) -> Result<Deleted> {
         self.run_command_and_read_response("EXPUNGE")
             .and_then(|lines| parse_expunge(lines, &mut self.unsolicited_responses_tx))
     }
@@ -693,7 +863,7 @@ impl<T: Read + Write> Session<T> {
     ///
     /// Alternatively, the client may fall back to using just [`Session::expunge`], risking the
     /// unintended removal of some messages.
-    pub fn uid_expunge<S: AsRef<str>>(&mut self, uid_set: S) -> Result<Vec<Uid>> {
+    pub fn uid_expunge<S: AsRef<str>>(&mut self, uid_set: S) -> Result<Deleted> {
         self.run_command_and_read_response(&format!("UID EXPUNGE {}", uid_set.as_ref()))
             .and_then(|lines| parse_expunge(lines, &mut self.unsolicited_responses_tx))
     }
@@ -1054,22 +1224,15 @@ impl<T: Read + Write> Session<T> {
     /// Specifically, the server will generally notify the client immediately via an untagged
     /// `EXISTS` response.  If the server does not do so, the client MAY issue a `NOOP` command (or
     /// failing that, a `CHECK` command) after one or more `APPEND` commands.
-    pub fn append<S: AsRef<str>, B: AsRef<[u8]>>(&mut self, mailbox: S, content: B) -> Result<()> {
-        let content = content.as_ref();
-        self.run_command(&format!(
-            "APPEND \"{}\" {{{}}}",
-            mailbox.as_ref(),
-            content.len()
-        ))?;
-        let mut v = Vec::new();
-        self.readline(&mut v)?;
-        if !v.starts_with(b"+") {
-            return Err(Error::Append);
+    ///
+    pub fn append<'a>(&'a mut self, mailbox: &'a str, content: &'a [u8]) -> AppendCmd<'a, T> {
+        AppendCmd {
+            session: self,
+            content,
+            mailbox,
+            flags: Vec::new(),
+            date: None,
         }
-        self.stream.write_all(content)?;
-        self.stream.write_all(b"\r\n")?;
-        self.stream.flush()?;
-        self.read_response().map(|_| ())
     }
 
     /// The [`SEARCH` command](https://tools.ietf.org/html/rfc3501#section-6.4.4) searches the
@@ -1204,10 +1367,10 @@ impl<T: Read + Write> Connection<T> {
             };
 
             let break_with = {
-                use imap_proto::{parse_response, Response, Status};
+                use imap_proto::{Response, Status};
                 let line = &data[line_start..];
 
-                match parse_response(line) {
+                match imap_proto::parser::parse_response(line) {
                     Ok((
                         _,
                         Response::Done {
@@ -1559,6 +1722,7 @@ mod tests {
             permanent_flags: vec![],
             uid_next: Some(2),
             uid_validity: Some(1257842737),
+            highest_mod_seq: None,
         };
         let mailbox_name = "INBOX";
         let command = format!("a1 EXAMINE {}\r\n", quote!(mailbox_name));
@@ -1605,6 +1769,7 @@ mod tests {
             ],
             uid_next: Some(2),
             uid_validity: Some(1257842737),
+            highest_mod_seq: None,
         };
         let mailbox_name = "INBOX";
         let command = format!("a1 SELECT {}\r\n", quote!(mailbox_name));
diff --git a/src/error.rs b/src/error.rs
index c062d56..dc57422 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -21,6 +21,7 @@ pub type Result<T> = result::Result<T, Error>;
 
 /// A set of errors that can occur in the IMAP client
 #[derive(Debug)]
+#[non_exhaustive]
 pub enum Error {
     /// An `io::Error` that occurred while trying to read or write to a network stream.
     Io(IoError),
@@ -43,8 +44,6 @@ pub enum Error {
     Validate(ValidateError),
     /// Error appending an e-mail.
     Append,
-    #[doc(hidden)]
-    __Nonexhaustive,
 }
 
 impl From<IoError> for Error {
@@ -99,7 +98,6 @@ impl fmt::Display for Error {
             Error::Bad(ref data) => write!(f, "Bad Response: {}", data),
             Error::ConnectionLost => f.write_str("Connection Lost"),
             Error::Append => f.write_str("Could not append mail to mailbox"),
-            Error::__Nonexhaustive => f.write_str("Unknown"),
         }
     }
 }
@@ -119,7 +117,6 @@ impl StdError for Error {
             Error::No(_) => "No Response",
             Error::ConnectionLost => "Connection lost",
             Error::Append => "Could not append mail to mailbox",
-            Error::__Nonexhaustive => "Unknown",
         }
     }
 
diff --git a/src/lib.rs b/src/lib.rs
index 48fc3d9..dcc6826 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -87,6 +87,7 @@ mod client;
 pub use crate::client::*;
 
 pub mod error;
+pub use error::{Error, Result};
 
 pub mod extensions;
 
diff --git a/src/parse.rs b/src/parse.rs
index 8b86f4c..1449a64 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -44,7 +44,7 @@ where
                 break Ok(things);
             }
 
-            match imap_proto::parse_response(lines) {
+            match imap_proto::parser::parse_response(lines) {
                 Ok((rest, resp)) => {
                     lines = rest;
 
@@ -127,13 +127,46 @@ pub fn parse_fetches(
 pub fn parse_expunge(
     lines: Vec<u8>,
     unsolicited: &mut mpsc::Sender<UnsolicitedResponse>,
-) -> Result<Vec<u32>> {
-    let f = |resp| match resp {
-        Response::Expunge(id) => Ok(MapOrNot::Map(id)),
-        resp => Ok(MapOrNot::Not(resp)),
-    };
+) -> Result<Deleted> {
+    let mut lines: &[u8] = &lines;
+    let mut expunged = Vec::new();
+    let mut vanished = Vec::new();
 
-    unsafe { parse_many(lines, f, unsolicited).map(|ids| ids.take()) }
+    loop {
+        if lines.is_empty() {
+            break;
+        }
+
+        match imap_proto::parser::parse_response(lines) {
+            Ok((rest, Response::Expunge(seq))) => {
+                lines = rest;
+                expunged.push(seq);
+            }
+            Ok((rest, Response::Vanished { earlier: _, uids })) => {
+                lines = rest;
+                vanished.extend(uids);
+            }
+            Ok((rest, data)) => {
+                lines = rest;
+                if let Some(resp) = handle_unilateral(data, unsolicited) {
+                    return Err(resp.into());
+                }
+            }
+            _ => {
+                return Err(Error::Parse(ParseError::Invalid(lines.to_vec())));
+            }
+        }
+    }
+
+    // If the server sends a VANISHED response then they must only send VANISHED
+    // in lieu of EXPUNGE responses for the rest of this connection, so it is
+    // always one or the other.
+    // https://tools.ietf.org/html/rfc7162#section-3.2.10
+    if !vanished.is_empty() {
+        Ok(Deleted::from_vanished(vanished))
+    } else {
+        Ok(Deleted::from_expunged(expunged))
+    }
 }
 
 pub fn parse_capabilities(
@@ -143,7 +176,7 @@ pub fn parse_capabilities(
     let f = |mut lines| {
         let mut caps = HashSet::new();
         loop {
-            match imap_proto::parse_response(lines) {
+            match imap_proto::parser::parse_response(lines) {
                 Ok((rest, Response::Capabilities(c))) => {
                     lines = rest;
                     caps.extend(c);
@@ -179,7 +212,7 @@ pub fn parse_noop(
             break Ok(());
         }
 
-        match imap_proto::parse_response(lines) {
+        match imap_proto::parser::parse_response(lines) {
             Ok((rest, data)) => {
                 lines = rest;
                 if let Some(resp) = handle_unilateral(data, unsolicited) {
@@ -200,7 +233,7 @@ pub fn parse_mailbox(
     let mut mailbox = Mailbox::default();
 
     loop {
-        match imap_proto::parse_response(lines) {
+        match imap_proto::parser::parse_response(lines) {
             Ok((rest, Response::Data { status, code, .. })) => {
                 lines = rest;
 
@@ -212,6 +245,9 @@ pub fn parse_mailbox(
 
                 use imap_proto::ResponseCode;
                 match code {
+                    Some(ResponseCode::HighestModSeq(seq)) => {
+                        mailbox.highest_mod_seq = Some(seq);
+                    }
                     Some(ResponseCode::UidValidity(uid)) => {
                         mailbox.uid_validity = Some(uid);
                     }
@@ -254,7 +290,8 @@ pub fn parse_mailbox(
                     }
                     MailboxDatum::List { .. }
                     | MailboxDatum::MetadataSolicited { .. }
-                    | MailboxDatum::MetadataUnsolicited { .. } => {}
+                    | MailboxDatum::MetadataUnsolicited { .. }
+                    | MailboxDatum::Search { .. } => {}
                 }
             }
             Ok((rest, Response::Expunge(n))) => {
@@ -286,8 +323,8 @@ pub fn parse_ids(
             break Ok(ids);
         }
 
-        match imap_proto::parse_response(lines) {
-            Ok((rest, Response::IDs(c))) => {
+        match imap_proto::parser::parse_response(lines) {
+            Ok((rest, Response::MailboxData(MailboxDatum::Search(c)))) => {
                 lines = rest;
                 ids.extend(c);
             }
@@ -322,8 +359,15 @@ pub(crate) fn handle_unilateral<'a>(
         Response::MailboxData(MailboxDatum::Recent(n)) => {
             unsolicited.send(UnsolicitedResponse::Recent(n)).unwrap();
         }
-        Response::MailboxData(MailboxDatum::Flags(_)) => {
-            // TODO: next breaking change:
+        Response::MailboxData(MailboxDatum::Flags(flags)) => {
+            unsolicited
+                .send(UnsolicitedResponse::Flags(
+                    flags
+                        .into_iter()
+                        .map(|s| Flag::from(s.to_string()))
+                        .collect(),
+                ))
+                .unwrap();
         }
         Response::MailboxData(MailboxDatum::Exists(n)) => {
             unsolicited.send(UnsolicitedResponse::Exists(n)).unwrap();
@@ -342,6 +386,11 @@ pub(crate) fn handle_unilateral<'a>(
                 })
                 .unwrap();
         }
+        Response::Vanished { earlier, uids } => {
+            unsolicited
+                .send(UnsolicitedResponse::Vanished { earlier, uids })
+                .unwrap();
+        }
         res => {
             return Some(res);
         }
@@ -569,4 +618,53 @@ mod tests {
         let ids: HashSet<u32> = ids.iter().cloned().collect();
         assert_eq!(ids, HashSet::<u32>::new());
     }
+
+    #[test]
+    fn parse_vanished_test() {
+        // VANISHED can appear if the user has enabled QRESYNC (RFC 7162), in response to
+        // SELECT/EXAMINE (QRESYNC); UID FETCH (VANISHED); or EXPUNGE commands. In the first
+        // two cases the VANISHED response will be a different type than expected
+        // and so goes into the unsolicited responses channel.
+        let lines = b"* VANISHED 3\r\n";
+        let (mut send, recv) = mpsc::channel();
+        let resp = parse_expunge(lines.to_vec(), &mut send).unwrap();
+
+        // Should be not empty, and have no seqs
+        assert!(!resp.is_empty());
+        assert_eq!(None, resp.seqs().next());
+
+        // Should have one UID response
+        let mut uids = resp.uids();
+        assert_eq!(Some(3), uids.next());
+        assert_eq!(None, uids.next());
+
+        // Should be nothing in the unsolicited responses channel
+        assert!(recv.try_recv().is_err());
+
+        // Test VANISHED mixed with FETCH
+        let lines = b"* VANISHED (EARLIER) 3:8,12,50:60\r\n\
+                      * 49 FETCH (UID 117 FLAGS (\\Seen \\Answered) MODSEQ (90060115194045001))\r\n";
+
+        let fetches = parse_fetches(lines.to_vec(), &mut send).unwrap();
+        match recv.try_recv().unwrap() {
+            UnsolicitedResponse::Vanished { earlier, uids } => {
+                assert!(earlier);
+                assert_eq!(uids.len(), 3);
+                assert_eq!(*uids[0].start(), 3);
+                assert_eq!(*uids[0].end(), 8);
+                assert_eq!(*uids[1].start(), 12);
+                assert_eq!(*uids[1].end(), 12);
+                assert_eq!(*uids[2].start(), 50);
+                assert_eq!(*uids[2].end(), 60);
+            }
+            what => panic!("Unexpected response in unsolicited responses: {:?}", what),
+        }
+        assert!(recv.try_recv().is_err());
+        assert_eq!(fetches.len(), 1);
+        assert_eq!(fetches[0].message, 49);
+        assert_eq!(fetches[0].flags(), &[Flag::Seen, Flag::Answered]);
+        assert_eq!(fetches[0].uid, Some(117));
+        assert_eq!(fetches[0].body(), None);
+        assert_eq!(fetches[0].header(), None);
+    }
 }
diff --git a/src/types/deleted.rs b/src/types/deleted.rs
new file mode 100644
index 0000000..90945c7
--- /dev/null
+++ b/src/types/deleted.rs
@@ -0,0 +1,180 @@
+use super::{Seq, Uid};
+use std::ops::RangeInclusive;
+
+/// An enum representing message sequence numbers or UID sequence sets returned
+/// in response to a `EXPUNGE` command.
+///
+/// The `EXPUNGE` command may return several `EXPUNGE` responses referencing
+/// message sequence numbers, or it may return a `VANISHED` response referencing
+/// multiple UID values in a sequence set if the client has enabled
+/// [QRESYNC](https://tools.ietf.org/html/rfc7162#section-3.2.7).
+///
+/// `Deleted` implements some iterators to make it easy to use. If the caller
+/// knows that they should be receiving an `EXPUNGE` or `VANISHED` response,
+/// then they can use [`seqs()`](#method.seqs) to get an iterator over `EXPUNGE`
+/// message sequence numbers, or [`uids()`](#method.uids) to get an iterator over
+/// the `VANISHED` UIDs. As a convenience `Deleted` also implents `IntoIterator`
+/// which just returns an iterator over whatever is contained within.
+///
+/// # Examples
+/// ```no_run
+/// # let domain = "imap.example.com";
+/// # let tls = native_tls::TlsConnector::builder().build().unwrap();
+/// # let client = imap::connect((domain, 993), domain, &tls).unwrap();
+/// # let mut session = client.login("name", "pw").unwrap();
+/// // Iterate over whatever is returned
+/// if let Ok(deleted) = session.expunge() {
+///     for id in &deleted {
+///         // Do something with id
+///     }
+/// }
+///
+/// // Expect a VANISHED response with UIDs
+/// if let Ok(deleted) = session.expunge() {
+///     for uid in deleted.uids() {
+///         // Do something with uid
+///     }
+/// }
+/// ```
+#[derive(Debug, Clone)]
+pub enum Deleted {
+    /// Message sequence numbers given in an `EXPUNGE` response.
+    Expunged(Vec<Seq>),
+    /// Message UIDs given in a `VANISHED` response.
+    Vanished(Vec<RangeInclusive<Uid>>),
+}
+
+impl Deleted {
+    /// Construct a new `Deleted` value from a vector of message sequence
+    /// numbers returned in one or more `EXPUNGE` responses.
+    pub fn from_expunged(v: Vec<u32>) -> Self {
+        Deleted::Expunged(v)
+    }
+
+    /// Construct a new `Deleted` value from a sequence-set of UIDs
+    /// returned in a `VANISHED` response
+    pub fn from_vanished(v: Vec<RangeInclusive<u32>>) -> Self {
+        Deleted::Vanished(v)
+    }
+
+    /// Return an iterator over message sequence numbers from an `EXPUNGE`
+    /// response. If the client is expecting sequence numbers this function
+    /// can be used to ensure only sequence numbers returned in an `EXPUNGE`
+    /// response are processed.
+    pub fn seqs(&self) -> impl Iterator<Item = Seq> + '_ {
+        match self {
+            Deleted::Expunged(s) => s.iter(),
+            Deleted::Vanished(_) => [].iter(),
+        }
+        .copied()
+    }
+
+    /// Return an iterator over UIDs returned in a `VANISHED` response.
+    /// If the client is expecting UIDs this function can be used to ensure
+    /// only UIDs are processed.
+    pub fn uids(&self) -> impl Iterator<Item = Uid> + '_ {
+        match self {
+            Deleted::Expunged(_) => [].iter(),
+            Deleted::Vanished(s) => s.iter(),
+        }
+        .flat_map(|range| range.clone())
+    }
+
+    /// Return if the set is empty
+    pub fn is_empty(&self) -> bool {
+        match self {
+            Deleted::Expunged(v) => v.is_empty(),
+            Deleted::Vanished(v) => v.is_empty(),
+        }
+    }
+}
+
+impl<'a> IntoIterator for &'a Deleted {
+    type Item = u32;
+    type IntoIter = Box<dyn Iterator<Item = u32> + 'a>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        match self {
+            Deleted::Expunged(_) => Box::new(self.seqs()),
+            Deleted::Vanished(_) => Box::new(self.uids()),
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn seq() {
+        let seqs = Deleted::from_expunged(vec![3, 6, 9, 12]);
+        let mut i = seqs.into_iter();
+        assert_eq!(Some(3), i.next());
+        assert_eq!(Some(6), i.next());
+        assert_eq!(Some(9), i.next());
+        assert_eq!(Some(12), i.next());
+        assert_eq!(None, i.next());
+
+        let seqs = Deleted::from_expunged(vec![]);
+        let mut i = seqs.into_iter();
+        assert_eq!(None, i.next());
+    }
+
+    #[test]
+    fn seq_set() {
+        let uids = Deleted::from_vanished(vec![1..=1, 3..=5, 8..=9, 12..=12]);
+        let mut i = uids.into_iter();
+        assert_eq!(Some(1), i.next());
+        assert_eq!(Some(3), i.next());
+        assert_eq!(Some(4), i.next());
+        assert_eq!(Some(5), i.next());
+        assert_eq!(Some(8), i.next());
+        assert_eq!(Some(9), i.next());
+        assert_eq!(Some(12), i.next());
+        assert_eq!(None, i.next());
+
+        let uids = Deleted::from_vanished(vec![]);
+        assert_eq!(None, uids.into_iter().next());
+    }
+
+    #[test]
+    fn seqs() {
+        let seqs: Deleted = Deleted::from_expunged(vec![3, 6, 9, 12]);
+        let mut count: u32 = 0;
+        for seq in seqs.seqs() {
+            count += 3;
+            assert_eq!(seq, count);
+        }
+        assert_eq!(count, 12);
+    }
+
+    #[test]
+    fn uids() {
+        let uids: Deleted = Deleted::from_vanished(vec![1..=6]);
+        let mut count: u32 = 0;
+        for uid in uids.uids() {
+            count += 1;
+            assert_eq!(uid, count);
+        }
+        assert_eq!(count, 6);
+    }
+
+    #[test]
+    fn generic_iteration() {
+        let seqs: Deleted = Deleted::from_expunged(vec![3, 6, 9, 12]);
+        let mut count: u32 = 0;
+        for seq in &seqs {
+            count += 3;
+            assert_eq!(seq, count);
+        }
+        assert_eq!(count, 12);
+
+        let uids: Deleted = Deleted::from_vanished(vec![1..=6]);
+        let mut count: u32 = 0;
+        for uid in &uids {
+            count += 1;
+            assert_eq!(uid, count);
+        }
+        assert_eq!(count, 6);
+    }
+}
diff --git a/src/types/mailbox.rs b/src/types/mailbox.rs
index 1b87720..1cadba6 100644
--- a/src/types/mailbox.rs
+++ b/src/types/mailbox.rs
@@ -4,6 +4,7 @@ use std::fmt;
 /// Meta-information about an IMAP mailbox, as returned by
 /// [`SELECT`](https://tools.ietf.org/html/rfc3501#section-6.3.1) and friends.
 #[derive(Clone, Debug, Eq, PartialEq, Hash)]
+#[non_exhaustive]
 pub struct Mailbox {
     /// Defined flags in the mailbox.  See the description of the [FLAGS
     /// response](https://tools.ietf.org/html/rfc3501#section-7.2.6) for more detail.
@@ -35,6 +36,10 @@ pub struct Mailbox {
     /// The unique identifier validity value.  See [`Uid`] for more details.  If this is missing,
     /// the server does not support unique identifiers.
     pub uid_validity: Option<u32>,
+
+    /// The highest mod sequence for this mailbox. Used with
+    /// [Conditional STORE](https://tools.ietf.org/html/rfc4551#section-3.1.1).
+    pub highest_mod_seq: Option<u64>,
 }
 
 impl Default for Mailbox {
@@ -47,6 +52,7 @@ impl Default for Mailbox {
             permanent_flags: Vec::new(),
             uid_next: None,
             uid_validity: None,
+            highest_mod_seq: None,
         }
     }
 }
@@ -56,14 +62,15 @@ impl fmt::Display for Mailbox {
         write!(
             f,
             "flags: {:?}, exists: {}, recent: {}, unseen: {:?}, permanent_flags: {:?},\
-             uid_next: {:?}, uid_validity: {:?}",
+             uid_next: {:?}, uid_validity: {:?}, highest_mod_seq: {:?}",
             self.flags,
             self.exists,
             self.recent,
             self.unseen,
             self.permanent_flags,
             self.uid_next,
-            self.uid_validity
+            self.uid_validity,
+            self.highest_mod_seq,
         )
     }
 }
diff --git a/src/types/mod.rs b/src/types/mod.rs
index ddea581..5741f8f 100644
--- a/src/types/mod.rs
+++ b/src/types/mod.rs
@@ -169,6 +169,21 @@ impl Flag<'static> {
     }
 }
 
+impl<'a> fmt::Display for Flag<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match *self {
+            Flag::Seen => write!(f, "\\Seen"),
+            Flag::Answered => write!(f, "\\Answered"),
+            Flag::Flagged => write!(f, "\\Flagged"),
+            Flag::Deleted => write!(f, "\\Deleted"),
+            Flag::Draft => write!(f, "\\Draft"),
+            Flag::Recent => write!(f, "\\Recent"),
+            Flag::MayCreate => write!(f, "\\*"),
+            Flag::Custom(ref s) => write!(f, "{}", s),
+        }
+    }
+}
+
 impl<'a> From<String> for Flag<'a> {
     fn from(s: String) -> Self {
         if let Some(f) = Flag::system(&s) {
@@ -201,6 +216,9 @@ pub use self::name::{Name, NameAttribute};
 mod capabilities;
 pub use self::capabilities::Capabilities;
 
+mod deleted;
+pub use self::deleted::Deleted;
+
 /// re-exported from imap_proto;
 pub use imap_proto::StatusAttribute;
 
@@ -211,6 +229,7 @@ pub use imap_proto::StatusAttribute;
 /// Note that `Recent`, `Exists` and `Expunge` responses refer to the currently `SELECT`ed folder,
 /// so the user must take care when interpreting these.
 #[derive(Debug, PartialEq, Eq)]
+#[non_exhaustive]
 pub enum UnsolicitedResponse {
     /// An unsolicited [`STATUS response`](https://tools.ietf.org/html/rfc3501#section-7.2.4).
     Status {
@@ -271,6 +290,41 @@ pub enum UnsolicitedResponse {
         /// List of annotations that were changed.
         metadata_entries: Vec<String>,
     },
+
+    /// An unsolicited [`VANISHED` response](https://tools.ietf.org/html/rfc7162#section-3.2.10)
+    /// that reports a sequence-set of `UID`s that have been expunged from the mailbox.
+    ///
+    /// The `VANISHED` response is similar to the `EXPUNGE` response and can be sent wherever
+    /// an `EXPUNGE` response can be sent. It can only be sent by the server if the client
+    /// has enabled [`QRESYNC`](https://tools.ietf.org/html/rfc7162).
+    ///
+    /// The `VANISHED` response has two forms, one with the `EARLIER` tag which is used to
+    /// respond to a `UID FETCH` or `SELECT/EXAMINE` command, and one without an `EARLIER`
+    /// tag, which is used to announce removals within an already selected mailbox.
+    ///
+    /// If using `QRESYNC`, the client can fetch new, updated and deleted `UID`s in a
+    /// single round trip by including the `(CHANGEDSINCE <MODSEQ> VANISHED)`
+    /// modifier to the `UID SEARCH` command, as described in
+    /// [RFC7162](https://tools.ietf.org/html/rfc7162#section-3.1.4). For example
+    /// `UID FETCH 1:* (UID FLAGS) (CHANGEDSINCE 1234 VANISHED)` would return `FETCH`
+    /// results for all `UID`s added or modified since `MODSEQ` `1234`. Deleted `UID`s
+    /// will be present as a `VANISHED` response in the `Session::unsolicited_responses`
+    /// channel.
+    Vanished {
+        /// Whether the `EARLIER` tag was set on the response
+        earlier: bool,
+        /// The list of `UID`s which have been removed
+        uids: Vec<std::ops::RangeInclusive<u32>>,
+    },
+
+    /// An unsolicited [`FLAGS` response](https://tools.ietf.org/html/rfc3501#section-7.2.6) that
+    /// identifies the flags (at a minimum, the system-defined flags) that are applicable in the
+    /// mailbox. Flags other than the system flags can also exist, depending on server
+    /// implementation.
+    ///
+    /// See [`Flag`] for details.
+    // TODO: the spec doesn't seem to say anything about when these may be received as unsolicited?
+    Flags(Vec<Flag<'static>>),
 }
 
 /// This type wraps an input stream and a type that was constructed by parsing that input stream,
@@ -318,6 +372,7 @@ impl<D> ZeroCopy<D> {
     ///
     /// Only safe if `D` contains no references into the underlying input stream (i.e., the `owned`
     /// passed to `ZeroCopy::new`).
+    #[allow(dead_code)]
     pub(crate) unsafe fn take(self) -> D {
         self.derived
     }
diff --git a/tests/imap_integration.rs b/tests/imap_integration.rs
index f639684..997b2f5 100644
--- a/tests/imap_integration.rs
+++ b/tests/imap_integration.rs
@@ -1,8 +1,10 @@
+extern crate chrono;
 extern crate imap;
 extern crate lettre;
 extern crate lettre_email;
 extern crate native_tls;
 
+use chrono::{FixedOffset, TimeZone};
 use lettre::Transport;
 use std::net::TcpStream;
 
@@ -231,3 +233,160 @@ fn list() {
 
     // TODO: make a subdir
 }
+
+#[test]
+fn append() {
+    let to = "inbox-append1@localhost";
+
+    // make a message to append
+    let e: lettre::SendableEmail = lettre_email::Email::builder()
+        .from("sender@localhost")
+        .to(to)
+        .subject("My second e-mail")
+        .text("Hello world")
+        .build()
+        .unwrap()
+        .into();
+
+    // connect
+    let mut c = session(to);
+    let mbox = "INBOX";
+    c.select(mbox).unwrap();
+    //append
+    c.append(mbox, e.message_to_string().unwrap().as_bytes())
+        .finish()
+        .unwrap();
+
+    // now we should see the e-mail!
+    let inbox = c.uid_search("ALL").unwrap();
+    // and the one message should have the first message sequence number
+    assert_eq!(inbox.len(), 1);
+    let uid = inbox.into_iter().next().unwrap();
+
+    // fetch the e-mail
+    let fetch = c.uid_fetch(format!("{}", uid), "(ALL UID)").unwrap();
+    assert_eq!(fetch.len(), 1);
+    let fetch = &fetch[0];
+    assert_eq!(fetch.uid, Some(uid));
+    let e = fetch.envelope().unwrap();
+    assert_eq!(e.subject, Some(&b"My second e-mail"[..]));
+
+    // and let's delete it to clean up
+    c.uid_store(format!("{}", uid), "+FLAGS (\\Deleted)")
+        .unwrap();
+    c.expunge().unwrap();
+
+    // the e-mail should be gone now
+    let inbox = c.search("ALL").unwrap();
+    assert_eq!(inbox.len(), 0);
+}
+
+#[test]
+fn append_with_flags() {
+    use imap::types::Flag;
+
+    let to = "inbox-append2@localhost";
+
+    // make a message to append
+    let e: lettre::SendableEmail = lettre_email::Email::builder()
+        .from("sender@localhost")
+        .to(to)
+        .subject("My third e-mail")
+        .text("Hello world")
+        .build()
+        .unwrap()
+        .into();
+
+    // connect
+    let mut c = session(to);
+    let mbox = "INBOX";
+    c.select(mbox).unwrap();
+    //append
+    let flags = vec![Flag::Seen, Flag::Flagged];
+    c.append(mbox, e.message_to_string().unwrap().as_bytes())
+        .flags(flags)
+        .finish()
+        .unwrap();
+
+    // now we should see the e-mail!
+    let inbox = c.uid_search("ALL").unwrap();
+    // and the one message should have the first message sequence number
+    assert_eq!(inbox.len(), 1);
+    let uid = inbox.into_iter().next().unwrap();
+
+    // fetch the e-mail
+    let fetch = c.uid_fetch(format!("{}", uid), "(ALL UID)").unwrap();
+    assert_eq!(fetch.len(), 1);
+    let fetch = &fetch[0];
+    assert_eq!(fetch.uid, Some(uid));
+    let e = fetch.envelope().unwrap();
+    assert_eq!(e.subject, Some(&b"My third e-mail"[..]));
+
+    // check the flags
+    let setflags = fetch.flags();
+    assert!(setflags.contains(&Flag::Seen));
+    assert!(setflags.contains(&Flag::Flagged));
+
+    // and let's delete it to clean up
+    c.uid_store(format!("{}", uid), "+FLAGS (\\Deleted)")
+        .unwrap();
+    c.expunge().unwrap();
+
+    // the e-mail should be gone now
+    let inbox = c.search("ALL").unwrap();
+    assert_eq!(inbox.len(), 0);
+}
+
+#[test]
+fn append_with_flags_and_date() {
+    use imap::types::Flag;
+
+    let to = "inbox-append3@localhost";
+
+    // make a message to append
+    let e: lettre::SendableEmail = lettre_email::Email::builder()
+        .from("sender@localhost")
+        .to(to)
+        .subject("My third e-mail")
+        .text("Hello world")
+        .build()
+        .unwrap()
+        .into();
+
+    // connect
+    let mut c = session(to);
+    let mbox = "INBOX";
+    c.select(mbox).unwrap();
+    // append
+    let date = FixedOffset::east(8 * 3600)
+        .ymd(2020, 12, 13)
+        .and_hms(13, 36, 36);
+    c.append(mbox, e.message_to_string().unwrap().as_bytes())
+        .flag(Flag::Seen)
+        .flag(Flag::Flagged)
+        .internal_date(date)
+        .finish()
+        .unwrap();
+
+    // now we should see the e-mail!
+    let inbox = c.uid_search("ALL").unwrap();
+    // and the one message should have the first message sequence number
+    assert_eq!(inbox.len(), 1);
+    let uid = inbox.into_iter().next().unwrap();
+
+    // fetch the e-mail
+    let fetch = c.uid_fetch(format!("{}", uid), "(ALL UID)").unwrap();
+    assert_eq!(fetch.len(), 1);
+    let fetch = &fetch[0];
+    assert_eq!(fetch.uid, Some(uid));
+    assert_eq!(fetch.internal_date(), Some(date));
+
+    // and let's delete it to clean up
+    c.uid_store(format!("{}", uid), "+FLAGS (\\Deleted)")
+        .unwrap();
+    c.expunge().unwrap();
+
+    // the e-mail should be gone now
+    let inbox = c.search("ALL").unwrap();
+    assert_eq!(inbox.len(), 0);
+}