well, i would NOT recommend running threads on anything above 5.2.12.. (depends how your php.ini is setup too)
we use deprecated functions (will be fix0red in v8) that 5.3 and above decided upon...
i found this out on my CentOS box when i also easyapache'd to 5.3.1 as well as my local WAMP install.. twas a bummer..
and as for php 6, they are gonzo bonzo alltogether..
as far as drupal
1 of other patches and another(joomla too), they HAD problems and i'd expect them to have fixed it by now.. note: that the symptoms vary from 'not working at all' to 'bothersome warning messages'.. YMMV
wordpress dodged the deprecated issue, by being ahead of the curve..
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offending functions that currently exist in 7.5.4.2 and are deprecated in php 5.3+ are:
safe_mode()
set_magic_quotes_runtime()
ereg()
eregi()
split() <-- used all over!
spliti()
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for me, since i control my box and whatever php version runs on it.. it was a simple choice.. php 5.2.12 also since you gain nothing significant by running 5.3+ anyway..
it is your choice on your box(es), however and good luck
