phpBB2.x had a global purge setting, where topic purging could be disabled for the entire site, overriding individual forum settings.

As phpBB3.x does not have this setting, where a 2.x site happens to have individual forums with purge settings enabled but the global setting disabled (and therefore NO purging occurs), upon conversion purging will start again... leading to unexpected loss of data.

I've been personally impacted by this problem, and would like to strongly recommend that for forums with the global purge setting set to disabled, one of the following be done:

• do not import purging settings for individual forums, set to no purge; or
• check for the scenario where purging is enabled for individual forums but globally disabled, and give a CLEAR warning to the administrator that purging will start occurring unless they disable it for each forum immediately

Otherwise, users will lose data as soon as the purging kicks in. As this behaviour is a change from 2.x, the current scenario is not acceptable.