diff --git a/data/Dockerfiles/rspamd/Dockerfile b/data/Dockerfiles/rspamd/Dockerfile
index 13e56357b..534ed943e 100644
--- a/data/Dockerfiles/rspamd/Dockerfile
+++ b/data/Dockerfiles/rspamd/Dockerfile
@@ -2,7 +2,7 @@ FROM debian:trixie-slim
 LABEL maintainer="The Infrastructure Company GmbH <info@servercow.de>"
 
 ARG DEBIAN_FRONTEND=noninteractive
-ARG RSPAMD_VER=rspamd_4.1.4-1~beb659b
+ARG RSPAMD_VER=rspamd_4.2.1-1~b7a16ae
 ARG CODENAME=trixie
 ENV LC_ALL=C
 
diff --git a/data/conf/rspamd/lua/rspamd.local.lua b/data/conf/rspamd/lua/rspamd.local.lua
index 313ba7e90..5d7bcaaf3 100644
--- a/data/conf/rspamd/lua/rspamd.local.lua
+++ b/data/conf/rspamd/lua/rspamd.local.lua
@@ -856,6 +856,8 @@ rspamd_config:register_symbol({
 
             local seen_cte
             local newline_s = newline(task)
+            -- use the CTE add_text_footer actually applied
+            local new_cte = rewrite.new_cte or 'quoted-printable'
 
             local function rewrite_ct_cb(name, hdr)
               if rewrite.need_rewrite_ct then
@@ -877,13 +879,13 @@ rspamd_config:register_symbol({
                   return
                 elseif name:lower() == 'content-transfer-encoding' then
                   out[#out + 1] = string.format('%s: %s',
-                      'Content-Transfer-Encoding', 'quoted-printable')
+                      'Content-Transfer-Encoding', new_cte)
                   -- update Content-Transfer-Encoding header
                   task:set_milter_reply({
                     remove_headers = {['Content-Transfer-Encoding'] = 0},
                   })
                   task:set_milter_reply({
-                    add_headers = {['Content-Transfer-Encoding'] = 'quoted-printable'}
+                    add_headers = {['Content-Transfer-Encoding'] = new_cte}
                   })
                   seen_cte = true
                   return
@@ -895,7 +897,7 @@ rspamd_config:register_symbol({
             task:headers_foreach(rewrite_ct_cb, {full = true})
 
             if not seen_cte and rewrite.need_rewrite_ct then
-              out[#out + 1] = string.format('%s: %s', 'Content-Transfer-Encoding', 'quoted-printable')
+              out[#out + 1] = string.format('%s: %s', 'Content-Transfer-Encoding', new_cte)
             end
 
             -- End of headers
@@ -914,7 +916,7 @@ rspamd_config:register_symbol({
                 out_parts[#out_parts + 1] = o
                 out_parts[#out_parts + 1] = newline_s
               else
-                local removePrefix = "--\x0D\x0AContent-Type"
+                local removePrefix = "--\x0D\x0AContent-"
                 if string.lower(string.sub(tostring(o[1]), 1, string.len(removePrefix))) == string.lower(removePrefix) then
                   o[1] = string.sub(tostring(o[1]), string.len("--\x0D\x0A") + 1)
                 end
diff --git a/docker-compose.yml b/docker-compose.yml
index a22d9e8ca..e9c256570 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -84,7 +84,7 @@ services:
             - clamd
 
     rspamd-mailcow:
-      image: ghcr.io/mailcow/rspamd:4.1.4-1
+      image: ghcr.io/mailcow/rspamd:4.2.1-1
       stop_grace_period: 30s
       depends_on:
         - dovecot-mailcow