Hi kynetguy,
My problem is that it doesn't keep some settings changes permanently. It only keeps an admin password change for one login and then defaults back to a system generated one. Thankfully it's a strong one, but I have to retrieve it using the 'Forgot Password' link.
It also periodically loses the 'Number Called When Door Bell Pressed' setting and it reverts to the extension number I used for testing before I installed it. I know when that happens because that test number was my extension and I get the call.
Apart from that it is working fine with firmware v10.0.1.6. Although Grandstream have asked me to update the firmware to v10.0.3.10 I haven't done that yet. I'm waiting for the normal approval process to occur between Grandstream and 3CX that John described. I don't have the nerve to upgrade it before that happens. Perhaps that is silly but I'll wait a little longer as it is working ok as I mentioned.