On my localhost clone I have upgraded from CB 1.9.1 to CB 2.0.3, and upgraded all my add-ons (CB Antispam, CB Auto Actions, CB Conditional) for the new CB.

Then I installed CB Subs GPL 4.0 and every plugin has a green tick under 'Installed' except for CB Paid Subscriptions - en-GB 4.0.0-rc.1 which has the brown triangle indicating that "This plugin is not compatible with your current CB version".

cbplug_lang_cbsubs_en-GB-4.0.0-rc.1.zip was installed as part of the upgrade and there were no errors or warnings.

Joomla version is 2.5.27

I have run CB Tools and the 'Check Community Builder Database' gives the following in red:
Core CB database structure differences:
Table #__comprofiler Storage Engine is MyISAM instead of InnoDB
Table #__comprofiler_fields Column displaytitle exists but should not exist
Table #__comprofiler_plugin Column access exists but should not exist
Table #__comprofiler_tabs Column useraccessgroupid exists but should not exist

All the other Tools show green throughout.

Thanks Nant. I'll download and install it.

I've downloaded and installed the latest nightly build of CBSubs 4.0 rc1 (CBSubs-4.0.0-rc.1.ci.2014.10.22.00.20-unzip1st-14227b9ad.zip) and nothing has changed.

This build appears to date from 22nd October 2014 - have I used the correct file?

In addition, as I have been looking around the pages I've noticed that all my CB configuration settings have been lost.

Perhaps I should recreate my cloned site and start again?

I re-installed everything.

In addition, as I have been looking around the pages I've noticed that all my CB configuration settings have been lost.

The first time I tried to install CB 2.0.3 I received some PHP warnings - something to do with being unable to re-define a few variables - but when I tried again the install ran without errors.

Perhaps I should recreate my cloned site and start again?