PostgreSQL, OpenSSL, and the GPL

One interesting thing of note is the recent transition of readline from GPLv2 to GPLv3. So, any software which is licensed under GPLv2-only also now has a similar incompatibility issue with readline.

I'm not sure how much software that actually impacts, but I don't think anyone's been paying as much attention to that sort of problem (upgrades introducing newly incompatible licensing) as they ought to.