What's core's CVS name?

We are talking about a name of the core on CVS, in XOOPS Cube project forum. Now, developers are writing next ideas of XOOPS Cube. But, those are not on CVS, because the CVS naming convention didn't consider how handle difference between PHP4 edition and PHP5 edition. Plus, the next version of XOOPS Cube may have big difference from the current version and may be unable to fit for Legacy.

Tom proposed to put each edition to each CVS module and keep PHP4 edition for Legacy. Nobunobu proposed to put those editions to one place and separate editions by using branches on the place.

Tom's idea is good to keep two editions. But, developers can not write code for the plural editions.

Nobunobu's idea is realistic. But, if the next version of XOOPS Cube can not fit for Legacy, "merge" means that Legacy's core disappears.

Do you think that we should include PHP version number to a name of CVS? Or, should we use branches well? Write your opinion to the forum.