diff --git a/eo-redmine-mailfilter.sh b/eo-redmine-mailfilter.sh
index 99b391a..0aeaf3a 100755
--- a/eo-redmine-mailfilter.sh
+++ b/eo-redmine-mailfilter.sh
@@ -1,12 +1,12 @@
 #!/bin/sh
 
-if ! echo $RECIPIENT | grep -q '^support-[a-z-]*@.*$'; then
+if ! echo $RECIPIENT | grep -q '^support-[a-z0-9-]*@.*$'; then
         exit 1
 fi
 
 export REDMINE_KEY=`cat /etc/redmine-key`
 export REDMINE_URL='https://dev.entrouvert.org'
 
-export PROJECT=`echo $RECIPIENT | sed 's/support-\([a-z-]*\)@.*/\1/'`
+export PROJECT=`echo $RECIPIENT | sed 's/support-\([a-z0-9-]*\)@.*/\1/'`
 
 python /usr/bin/mail2redmine.py