Hello
Just my 10 cents on that one.
If you are programming in assembler, it should be less critical.
Only reason you would need to upgrade to V5.0 is if you change to a newer MCU, which is not supported by V3.0.
We will not produce service packs to upgrade V3.1 to support new derivatives. Going forward service packs will be created for V5.x only.
Note that latest HC08 release is V5.1, where you also have support for RS08 CPU.
CrasyCat