I have the same issues. I had a great base going on 0.17.34 but decided to download latest 0.17.47...should have read this forum first. I tried reverting back but map got updated and now is not compatible with the earlier version. I am in limbo.

It turns out that I had not picked up the OpteraLib mod (new for 0.17? I had developed an extensive LTN network on 0.16 without it.). Your prompt caued me to go back into the mods list and take a close look at all them mods. Thanks, DaleStan!

I just migrated from Factorio v0.16 to v0.17.35 and started a new base. However, I do not seem to have my LTN mod enabled— I do not see the LTN technologies in my research queue, the mod shows up as red in mods list, and I haven’t found any update that hasn’t been installed. I know that update 17.34...