Having the same issue. This is indeed a thing that has hesitated me from upgrading, just like the OP.
An idea I would have is upgrade and restore without config, and then restoire a backup of the config files, but with the following files removed:
/etc/config/network
/etc/config/wireless
/etc/config/dhcp
/etc/config/firewall
I then would need to re-configure all firewall and wifi stuff? (I have not changed much else, have i?)
Though maybe I can leave the wifi as it is, as this page explains:
DSA support does not affect wireless configuration in
/etc/config/wireless
That would already help a lot…
Such a breaking change with no migration path is really annoying. I mean if we had a tool or so to convert the config files and I can put them in there, that would help a lot.
Okay at least with attended-sysupgrade we may keep the installed packages. (Edit: Okay, no apparently major upgrades are not supported, it says the version is up-to-date. )
For reference here the specs/error message:
OpenWrt 22.03.7 to OpenWRT 23.05.5 (r24106-10cc5fcd00)
Model: GL.iNet GL-B1300
Platform: ipq40xx/generic
Thu Oct 31 11:27:47 CET 2024 upgrade: The device is supported, but the config is incompatible to the new image (1.0->1.1). Please upgrade without keeping config (sysupgrade -n). Thu Oct 31 11:27:47 CET 2024 upgrade: Config cannot be migrated from swconfig to DSA Image check failed.
It seems for my device the migration was done in v23.