There are several problems with this approach.
The update nag: I actually wanted to include one, but
@IcySon55 , the actual founder of this program, was against one. There are hints and links to Kuriimu 2 however in the Final Version of K1.
The plugin incompatibility monicker: Due to the severe restructuring, the engine is incapabable of identifying an old plugin in any way. It's just not technically feasable, so this feature can not be implemented.
Program update: K1 has no update mechanism at all and introducing one was challenging enough for K2 alone. It would just not be worth the time for the effect.
The two programs are just technically too different to "hide" this as any other update.
We want the user to know that "something" (meaning basically everything) changed.