I now have 4 sites running ClassicPress and Bulletproof Security Pro on all of them.
Earlier today I tried updating the plugin as usual via standard WP/CP “Update Plugins” and got error as below
(Update Failed: The package could not be installed. PCLZIP_ERR_BAD_FORMAT (-10) : Unable to find End of Central Dir Record signature)
BPS Pro also has an internal facility to update from zip file within itself and this worked fine, so not critical, but it would be good to establish whether ClassicPress has a possible compatibility issue with standard plugin update method (and ways for plugin/theme authors to mitigate this if so).
Worth noting that the standard update method worked fine on all my WP sites, and to test I also tried reverting a CP site that failed to update to WP, at which point the BPS update installed with no issues, and then switching back to CP (working fine), so it isn’t an issue with my web host’s setup (the error above can apparently be caused by server site issues)
Alternatively/additionally perhaps BPS Pro is checking core files when doing an update. If this is the case, it would be useful to know from CP developers where the error above might be triggered before (I will also raise this issue direct with the developer of BPS Pro at same link on his forum as in my original post at