All schematics that are being removed from the game, or archived, will no longer be trainable once 4.0 goes live. You also cannot reverse engineer those schematics to learn new ones.
This is one thing I haven't seen answered anywhere. I have stopped leveling my synthweaver since the 4.0 update is so close. Will those patterns that will be "archived" still be available from the trainers once 4.0 hits? While we know the new patterns are stat-wise superior, I may still want some of the "archived" patterns for appearance sake. Can I still train those or should I scramble to get to 500 before 4.0?
Hopefully that answers the question!