I'm not getting any response over on the EE forums, so I figured I'd post my issue here as well.
I’m attempting to update an EE site from 2.5.5 to 2.7.3, the installer process runs smoothly, but then I get the following error on the front end & when accessing control panel:
Call to undefined function reduce_double_slashes() in admin/expressionengine/libraries/Extensions.php on line 194
I have rolled my local repo back to 2.5.5, restored my old db, and applied the update again with the same results.
Has anyone else experienced this issue when upgrading to EE 2.7.x?