I'm thinking of updating my php from version 5.3 to version 5.5.
I was wondering if 5.5 is backwards compatible with 5.3 as it is 'just' a minor update (eg not 5.3 to 6.4). Am I running into problems if I just update the php installation via https://serverfault.com/a/420288/124883 ? Is there a way (just like nginx's 'configtest' option to test the dependencies? )
Or is it possible to have both versions running simultaneous as I don't have a test-server only a live server??