I was using the Nexthause SyncJe client (commercial). None of the Funambol clients will work because they all try to speak SyncML V1.2 which the older Sync4j server doesn't support (another reason to switch to Funambol V6 server)
On an unrelated note, the Zimbra Mobile forums no longer show up until you login, which means this particular thread isn't visible until you login. Since it's linked from various other sites (including the Funambol site), perhaps we could allow it to be visible to non-logged-in users, or move it to the developer's forum (somehow without breaking the link
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