diff --git a/go.mod b/go.mod
index e2da8e75d34c32710ff11240984c33caf31ee592..65488a5df4adfa9655bdcd80c13393af4fbc9795 100644
--- a/go.mod
+++ b/go.mod
@@ -2,4 +2,4 @@ module git.autistici.org/ai3/tools/smtpd-pipe
 
 go 1.16
 
-require github.com/chrj/smtpd v0.3.0
+require github.com/chrj/smtpd v0.3.1
diff --git a/go.sum b/go.sum
index 7521695a646ab51024bda8b721ae8660b1b1b800..e959044cffb3af2ea5ad5ae75c7aa3abe66c802b 100644
--- a/go.sum
+++ b/go.sum
@@ -2,4 +2,6 @@ github.com/chrj/smtpd v0.2.0 h1:QGbE4UQz7sKjvXpRgNLuiBOjcWTzBKu/dj0hyDLpD14=
 github.com/chrj/smtpd v0.2.0/go.mod h1:1hmG9KbrE10JG1SmvG79Krh4F6713oUrw2+gRp1oSYk=
 github.com/chrj/smtpd v0.3.0 h1:cw1LSHDOz7N3XbkcZSF/bue9dh7ATKk5ZksfBztV6b0=
 github.com/chrj/smtpd v0.3.0/go.mod h1:1hmG9KbrE10JG1SmvG79Krh4F6713oUrw2+gRp1oSYk=
+github.com/chrj/smtpd v0.3.1 h1:kogHFkbFdKaoH3bgZkqNC9uVtKYOFfM3uV3rroBdooE=
+github.com/chrj/smtpd v0.3.1/go.mod h1:JtABvV/LzvLmEIzy0NyDnrfMGOMd8wy5frAokwf6J9Q=
 github.com/eaigner/dkim v0.0.0-20150301120808-6fe4a7ee9cfb/go.mod h1:FSCIHbrqk7D01Mj8y/jW+NS1uoCerr+ad+IckTHTFf4=
diff --git a/vendor/github.com/chrj/smtpd/go.mod b/vendor/github.com/chrj/smtpd/go.mod
index f5c23917ee3f98a36ae8d7826768904f892387d5..a883ba1219dd2097a07514081833595eafc9262a 100644
--- a/vendor/github.com/chrj/smtpd/go.mod
+++ b/vendor/github.com/chrj/smtpd/go.mod
@@ -1,5 +1,3 @@
 module github.com/chrj/smtpd
 
 go 1.14
-
-require github.com/eaigner/dkim v0.0.0-20150301120808-6fe4a7ee9cfb
diff --git a/vendor/github.com/chrj/smtpd/go.sum b/vendor/github.com/chrj/smtpd/go.sum
deleted file mode 100644
index 0d11b77962f5d6dc03e3ac68169d6c4b51dbc645..0000000000000000000000000000000000000000
--- a/vendor/github.com/chrj/smtpd/go.sum
+++ /dev/null
@@ -1,2 +0,0 @@
-github.com/eaigner/dkim v0.0.0-20150301120808-6fe4a7ee9cfb h1:17kQ+7S0aEyRhZd9KCAofvKlL1N1/w+zUZKaxpLFpM0=
-github.com/eaigner/dkim v0.0.0-20150301120808-6fe4a7ee9cfb/go.mod h1:FSCIHbrqk7D01Mj8y/jW+NS1uoCerr+ad+IckTHTFf4=
diff --git a/vendor/modules.txt b/vendor/modules.txt
index 39c2474cf25e95f5edfd3537ad910fce5dc2fc3e..53383970448da8dcdc76ab3b9e28bc074e64ff59 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -1,3 +1,3 @@
-# github.com/chrj/smtpd v0.3.0
+# github.com/chrj/smtpd v0.3.1
 ## explicit
 github.com/chrj/smtpd