How will the transition to PHP5 be handled? I mean, will it be similar to the switch from apache1.3 to 2.0 or will it just happen invisibly? Any wild guesses at to when such a thing might be possible?
I see that the toaster is listed to not support php5 but the compnoents of phpmyadmin and squirrelmail both do. Are there any other components that would need the upgrade to support php5?
It's an invisible transition. If you want to use PHP 5 now, do so but be aware that you might have issues. If the stuff that's important to you in the toaster has support for PHP 5, then by all means, use it.