This issue comes up from time to time for me, and I hope someone can help. Occasionally I need to make minor revisions to a score that was engraved with LilyPond version 1.4.12. That version was long before I started trying to use the program, so I don't have that version. Anyway, every time I try to revise the source so that it will compile in v. 2.16 or 2.18, I screw up something and it makes a mess and pretty soon I'm frustrated and move on to something more productive.