diff --git a/data/conf/rspamd/lua/rspamd.local.lua b/data/conf/rspamd/lua/rspamd.local.lua
index 2bf328e5b..9d0a58bcf 100644
--- a/data/conf/rspamd/lua/rspamd.local.lua
+++ b/data/conf/rspamd/lua/rspamd.local.lua
@@ -550,13 +550,13 @@ rspamd_config:register_symbol({
     -- determine newline type
     local function newline(task)
       local t = task:get_newlines_type()
-    
+
       if t == 'cr' then
         return '\r'
       elseif t == 'lf' then
         return '\n'
       end
-    
+
       return '\r\n'
     end
     -- retrieve footer
@@ -564,7 +564,7 @@ rspamd_config:register_symbol({
       if err or type(data) ~= 'string' then
         rspamd_logger.infox(rspamd_config, "domain wide footer request for user %s returned invalid or empty data (\"%s\") or error (\"%s\")", uname, data, err)
       else
-        
+
         -- parse json string
         local footer = cjson.decode(data)
         if not footer then
@@ -613,26 +613,30 @@ rspamd_config:register_symbol({
             if footer.plain and footer.plain ~= "" then
               footer.plain = lua_util.jinja_template(footer.plain, replacements, true)
             end
-  
+
             -- add footer
             local out = {}
             local rewrite = lua_mime.add_text_footer(task, footer.html, footer.plain) or {}
-        
+
             local seen_cte
             local newline_s = newline(task)
-        
+
             local function rewrite_ct_cb(name, hdr)
               if rewrite.need_rewrite_ct then
                 if name:lower() == 'content-type' then
-                  local nct = string.format('%s: %s/%s; charset=utf-8',
-                      'Content-Type', rewrite.new_ct.type, rewrite.new_ct.subtype)
+                  -- include boundary if present
+                  local boundary_part = rewrite.new_ct.boundary and
+                    string.format('; boundary="%s"', rewrite.new_ct.boundary) or ''
+                  local nct = string.format('%s: %s/%s; charset=utf-8%s',
+                      'Content-Type', rewrite.new_ct.type, rewrite.new_ct.subtype, boundary_part)
                   out[#out + 1] = nct
-                  -- update Content-Type header
+                  -- update Content-Type header (include boundary if present)
                   task:set_milter_reply({
                     remove_headers = {['Content-Type'] = 0},
                   })
                   task:set_milter_reply({
-                    add_headers = {['Content-Type'] = string.format('%s/%s; charset=utf-8', rewrite.new_ct.type, rewrite.new_ct.subtype)}
+                    add_headers = {['Content-Type'] = string.format('%s/%s; charset=utf-8%s',
+                      rewrite.new_ct.type, rewrite.new_ct.subtype, boundary_part)}
                   })
                   return
                 elseif name:lower() == 'content-transfer-encoding' then
@@ -651,16 +655,16 @@ rspamd_config:register_symbol({
               end
               out[#out + 1] = hdr.raw:gsub('\r?\n?$', '')
             end
-        
+
             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')
             end
-        
+
             -- End of headers
             out[#out + 1] = newline_s
-        
+
             if rewrite.out then
               for _,o in ipairs(rewrite.out) do
                 out[#out + 1] = o