diff --git a/go.mod b/go.mod
index 2b3f9a16..24aed90d 100644
--- a/go.mod
+++ b/go.mod
@@ -13,7 +13,7 @@ require (
 	github.com/emersion/go-milter v0.3.3
 	github.com/emersion/go-msgauth v0.6.6
 	github.com/emersion/go-sasl v0.0.0-20220912192320-0145f2c60ead
-	github.com/emersion/go-smtp v0.16.0
+	github.com/emersion/go-smtp v0.20.1
 	github.com/foxcpp/go-dovecot-sasl v0.0.0-20200522223722-c4699d7a24bf
 	github.com/foxcpp/go-imap-backend-tests v0.0.0-20220105184719-e80aa29a5e16
 	github.com/foxcpp/go-imap-i18nlevel v0.0.0-20200208001533-d6ec88553005
diff --git a/go.sum b/go.sum
index ddf6797a..12a49e7c 100644
--- a/go.sum
+++ b/go.sum
@@ -286,8 +286,8 @@ github.com/emersion/go-sasl v0.0.0-20191210011802-430746ea8b9b/go.mod h1:G/dpzLu
 github.com/emersion/go-sasl v0.0.0-20200509203442-7bfe0ed36a21/go.mod h1:iL2twTeMvZnrg54ZoPDNfJaJaqy0xIQFuBdrLsmspwQ=
 github.com/emersion/go-sasl v0.0.0-20220912192320-0145f2c60ead h1:fI1Jck0vUrXT8bnphprS1EoVRe2Q5CKCX8iDlpqjQ/Y=
 github.com/emersion/go-sasl v0.0.0-20220912192320-0145f2c60ead/go.mod h1:iL2twTeMvZnrg54ZoPDNfJaJaqy0xIQFuBdrLsmspwQ=
-github.com/emersion/go-smtp v0.16.0 h1:eB9CY9527WdEZSs5sWisTmilDX7gG+Q/2IdRcmubpa8=
-github.com/emersion/go-smtp v0.16.0/go.mod h1:qm27SGYgoIPRot6ubfQ/GpiPy/g3PaZAVRxiO/sDUgQ=
+github.com/emersion/go-smtp v0.20.1 h1:kW8Nkzomjk6W1ebfUYy6wAYThukCzD9MFOkFnragOHc=
+github.com/emersion/go-smtp v0.20.1/go.mod h1:qm27SGYgoIPRot6ubfQ/GpiPy/g3PaZAVRxiO/sDUgQ=
 github.com/emersion/go-textwrapper v0.0.0-20160606182133-d0e65e56babe/go.mod h1:aqO8z8wPrjkscevZJFVE1wXJrLpC5LtJG7fqLOsPb2U=
 github.com/emersion/go-textwrapper v0.0.0-20200911093747-65d896831594 h1:IbFBtwoTQyw0fIM5xv1HF+Y+3ZijDR839WMulgxCcUY=
 github.com/emersion/go-textwrapper v0.0.0-20200911093747-65d896831594/go.mod h1:aqO8z8wPrjkscevZJFVE1wXJrLpC5LtJG7fqLOsPb2U=