Software can be upgraded with no cost to the original developer! I think this shows one of the greatest things that Open Source and GPL offer. The original developer did'nt have to pay a cent to see it's software evolve on a new platform or be up to date. The rules can seem unfair, but the same rules allow him to sell the app also! He can get the new code (for free), and state that he is the original developer in his marketing.

It would be nice to try to contact the former developer when someone will modify their software...

We have to focus on starters, the advanced civilizations would hide themselves. So.. we should analyze the numbers on how many low-technical civilizations could be out there. We have to be more (in quantity) than the advanced ones (like the species in our planet, there are few organized species). And it should be easier to find the ones like us.

It's interesting the attribution clause included on these licenses. We have many discussions about how manage attribution on open source projects. CPAL (https://www.socialtext.net/open/index.cgi?cpal) license gave us some points to consider when talking about attribution. This license allows you to put a limited attribution on the software "copyright notice, short phrase (10 words), graphic image and URL." GPL 3 has it's own clause on attribution resources (see clause 7) The way Ms-RL Ms-PL describes how attribution will be managed has another aproach from the previous licenses: They require you to respect any attribution notices that the original work has. So here we have an OSI approved license which can be used to preserve all your attribution notices...