The firmware I'm currently using is the beta 0.4.0 0.9.1 v0074.0 Build 200701 Beta.71362n

There seem to be a range of beta firmwares floating around for this device, but apart from the above the most recent I can find is Build 210409 (dated 2021-04-12).I've tried this firmware a couple of times but, although I can get good speed from it, it causes my device to lock up after a while.

Is that the last beta you released for this device? If not, what was the latest? If it was, are there any builds in between 200701 and 210409? I ask this because, although 200701 doesn't lock up my device, the VDSL connection is less stable than in build 210409.

I've tried upgraded my modem to V3 but the connection regularly dropped with that one, so I went back to my V2.