What we really want to do is to update to PHP 5.6, not because we need it's features (there are a few nice additions, but no big change) but because this will allow us to update PHPUnit to 5.x.
We are not there yet, but we can prepare and drop PHP 5.3 and 5.4. This is already done in almost all our code bases, and turns more and more into a source of confusion and possible frustration. For example, we can use the short array syntax everywhere, except in the following minor code bases:
- https://gerrit.wikimedia.org/r/351611 Wikidata.org
- https://gerrit.wikimedia.org/r/342435 Wikibase-Quality-Constraints
- https://gerrit.wikimedia.org/r/353842 ValueView