Hi.
First I wanted to report a bug that locked pipes ignore upgrade planner, but then I saw the problem.
So, now it is a feature request.
Would it be possible to keep the pipe configuration when a pipe is replaced? Now, when a pipe (of the other type or the same) is placed on an exiting locked pipe, it reset the configuration and connects to everything. It may be a nice additional way to reset the pipe, but with multiple tier of pipes "keep the configuration" behavior may be better. It would also allow for upgrade planner to work on them.

Hi! For some reason I didn't get a notification for this until now. I can definitely look into this, yes. It may take a bit since I'll be working on the 2.1 port in parallel, but hopefully fixing this will be straightforward.

Fixed with 2.1.7! If it's not fixed, let me know the subset of mods with which you can reproduce the issue. I tested it with steel pipes and manually defining the next_upgrade before processing the pipes