While most docs are pertinent to both ColdFusion and Lucee, there are several things that aren't that will keep you from migrating to Lucee if you are on ColdFusion.

CFDocs [1] is a nice site to check out which functions differ from each version, etc. (No affiliation to CFDocs, just use them quite often for work and have been the best resource for CFML that I have found)

[1]: http://cfdocs.org/