diff --git a/Cargo.lock b/Cargo.lock
index 9463be5..21487e6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -758,26 +758,26 @@ checksum = "7ef03e0a2b150c7a90d01faf6254c9c48a41e95fb2a8c2ac1c6f0d2b9aefc342"
 
 [[package]]
 name = "rustls"
-version = "0.20.6"
+version = "0.21.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5aab8ee6c7097ed6057f43c187a62418d0c05a4bd5f18b3571db50ee0f9ce033"
+checksum = "e32ca28af694bc1bbf399c33a516dbdf1c90090b8ab23c2bc24f834aa2247f5f"
 dependencies = [
  "log",
  "ring",
+ "rustls-webpki",
  "sct",
- "webpki",
 ]
 
 [[package]]
 name = "rustls-connector"
-version = "0.16.1"
+version = "0.18.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9c6a18f8d10f71bce9bca6eaeb80429460e652f3bcf0381f0c5f8954abf7b3b8"
+checksum = "67c8d6cf0e464eff7cee6ba0419f56a65d29999fc164dd719c8633fbb401365f"
 dependencies = [
  "log",
  "rustls",
  "rustls-native-certs",
- "webpki",
+ "rustls-webpki",
 ]
 
 [[package]]
@@ -801,6 +801,16 @@ dependencies = [
  "base64 0.13.0",
 ]
 
+[[package]]
+name = "rustls-webpki"
+version = "0.100.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d6207cd5ed3d8dca7816f8f3725513a34609c0c765bf652b8c3cb4cfd87db46b"
+dependencies = [
+ "ring",
+ "untrusted",
+]
+
 [[package]]
 name = "schannel"
 version = "0.1.20"
@@ -1104,16 +1114,6 @@ dependencies = [
  "wasm-bindgen",
 ]
 
-[[package]]
-name = "webpki"
-version = "0.22.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f095d78192e208183081cc07bc5515ef55216397af48b873e5edcd72637fa1bd"
-dependencies = [
- "ring",
- "untrusted",
-]
-
 [[package]]
 name = "winapi"
 version = "0.3.9"
diff --git a/Cargo.toml b/Cargo.toml
index cf4ba0e..cc3d8f9 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -21,7 +21,7 @@ test-full-imap = []
 
 [dependencies]
 native-tls = { version = "0.2.2", optional = true }
-rustls-connector = { version = "0.16.1", optional = true }
+rustls-connector = { version = "0.18.0", optional = true }
 regex = "1.0"
 bufstream = "0.1.3"
 imap-proto = "0.16.1"
@@ -33,7 +33,7 @@ ouroboros = "0.16.0"
 
 [dev-dependencies]
 lettre = "0.10"
-rustls-connector = "0.16.1"
+rustls-connector = "0.18.0"
 structopt = "0.3"
 
 # to make -Zminimal-versions work