This question is an exact duplicate of:
Is there any way to downgrade the apache version that installed in ubuntu 14.04.
Some packages are not working in 2.4 apache. So we decide to downgrade to the stable apache version
Apache 2.2 isn't in the official repos. You could try adding an old repos from 12.04 and installing from there, but it's probably best to try to fix your own server config.