Hi,
During a minor upgrade from version 3.18.0 to 3.18.1 I noticed that a few additional steps may need to be added to the following instructions:
http://matrix.squiz.net/resources/upgrading/standard-minor-upgrade-instructions
cd /home/websites/mysource_matrix
chown -R <apache_user>:<apache_group> data cache
chmod -R 755 .
chmod -R g+w data cache
I may have missed these steps detailed within other upgrade instructions, please accept my apologies if this is the case.
Cheers,
ZB