Coincidentally, I completely reinstalled my daily driver (Sony Xperia 10 III) yesterday.
Encouraged by this thread I flashed Android 13 via Emma and flashed the latest Sailfish OS 4.6.0.13 alongside the recommended software binaries SW_binaries_for_Xperia_Android_11_4.19_v9a_lena with the jolla flash script. I basically followed the installation instructions by jolla with the exception of the Android 13 base.
Color banding is gone. EDIT: I think some other users also reported this. The greenish banding is way less intrusive but on low backlight in a dark environment it is still noticeable. If I recall correct, the resulting colors of the Android 11 base in combination with the workaround of JacekJagosz were more natural. [X10II] [X10III] Color banding in low light conditions - #24 by JacekJagosz
No echoing issue reported. I have the impession that the device responds quicker and performs better overall, but this might be due to the “fresh install”.
But that didn’t affect my personal experiences with VoLTE. I have a pretty old sim card (> 10 years) from o2 germany. Calling via VoLTE works fine although I don’t get a ring back sound. Receiving SMS works fine but sending SMS is impossible*. SMS get transfered instantly if i switch VoLTE off though.
So you can expect improvements but I’m affraid not on the VoLTE side.
*Due to the fresh installation of SFOS 4.6.0.13 VoLTE was enabled by default and at my first test run I was able to send one sms. May be my phone wasn’t registered in a 4G cell already, but I wasn’t able to send another SMS afterwards.