diff --git a/IMAP-Sync.md b/IMAP-Sync.md
index f1e987e..f78b64c 100644
--- a/IMAP-Sync.md
+++ b/IMAP-Sync.md
@@ -1,5 +1,6 @@
 Sync email via IMAP from host1/domain1 to a subfolder on host2/domain2 via a cron/timer. Can be reversed as well, just update `Patterns` to exclude the subfolders from being cross-replicated (looped).
 
+ - https://isync.sourceforge.io/mbsync.html
  - Install the `isync` package: `apt-get update && apt-get install isync`
 
 Passwords for IMAP must be left on disk in plain text