Update 30.9.2016: W3 Total Cache v0.9.5.1 has been released today, which re-adds backward compatibility for third-party-plugins using their functions and classes. Maps Marker Pro and Leaflet Maps Marker will work properly out of the box with W3 Total Cache v0.9.5.1 even if the hotfix below was not applied.
The popular W3 Total Cache plugin was updated to v0.9.5 today. Unfortunately this update does not consider backward compatiblity for functions lots of other plugins – including Maps Marker Pro – are depending on. This is why updating to W3TC 0.9.5 can make parts of your WordPress backend unaccessible and you will the see the following error in the content area instead:
Fatal error: Call to undefined function w3_instance()...
As we are currently in the last steps of preparing the upcoming releases, we decided to publish a hotfix for this issue. That hotfix has been added to the current pro v2.7.3 release – so if you have downloaded Maps Marker Pro after Sep 26th, you are not affected from this issue and do not need to apply the hotfix. If you downloaded Maps Marker Pro before Sep 26th (and updated to W3 Total Cache v0.9.5) you need to follow this tutorial to apply the hotfix: download the hotfix from https://www.mapsmarker.com/hotfix-w3tc/pro-v2.7.3/compatibility-checks.zip unpack the file locally use ftp to overwrite the file compatiblity-checks.php on your server in the directory
As an alternative you can also edit the file
/wp-content/plugins/leaflet-maps-marker-pro/inc/compatibility-checks.php directly and delete the W3TC compatibility check (on line 65-94 for v2.7.3)
Please be aware that the tutorial above only applies to Maps Marker Pro – if you are looking for a tutorial on how to apply the hotfix for Leaflet Maps Marker, please click here. We are sorry for this inconvenience. For future version we will try to make sure that our code runs properly even if function from third-party plugins are removed or not accessible anymore…