@fredtcaroli hi!
That’s a great question and I feel like we should probably publish a guide for it… But it’s not so complicated actually. @skshetry outlined it here: Remove/Redefine Stage - #12 by skshetry
It depends a little bit what kind of 0.94 project you had because usually they have one .dvc file per stage but the feature to have a single pipelines file (pipelines.yaml) already existed (it was just partially hidden).
The best way is to combine all .dvc files into the new dvc.yaml manually (see expected format) and run dvc repro at the end to check the file and stages are valid, and to regenerate the outputs and put them in cache. You could skip the cache part if they’re already there with --no-commit.
It may also be possible to skip dvc repro entirely by using dvc commit instead but I think this is more advanced and a little difficult since it may expect you to also create dvc.lock which is not that easy to edit manually.