This is the post where I asked about upgrading my kernel after upgrading a DietPi system from Bullseye → Bookworm & was instructed to “start fresh”
The Matrix Synapse server in the OP is now running on DietPi v9.7.1 - bullseye, Debian 11 on a Raspberry Pi 4.
I had a 2nd Raspberry Pi 4 sitting around, so I installed the DietPi Bookworm image on it and the kernel would only update to 6.6.31+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.6.31-1+rpt1 (2024-05-29) aarch64 GNU/Linux
I have a totally different DietPi system running on a Pine64 Rock64, which is running different software with a kernel of 6.6.44-current-rockchip64 #1 SMP PREEMPT Sat Aug 3 06:54:42 UTC 2024 aarch64
My plan is to use a 2nd Pine64 Rock64 for a Matrix Synapse server running Bookworm, because it’s receiving kernel updates, but I still have the same original issue in the OP about PostgreSQL versions 13 vs 15.