500 error on CBSubs plan edit!

Disabled "all but core" - except I cannot disable "CB Paid Subscriptions - en-GB" ( as its a language plugin!) ... is it safe to delete before migration? Or should I leave it alone?

You don't need to worry about language or template plugins. They don't load any APIs.

Well, since I want to get rolling on this, I'm trying another experiment (no big hardship if I have to rollback the dev server, since I've already done it several times on this migration testing...)

Downloaded base packages CB & CBsubs
Disabled Kunena Integration, and CBsubs
Disabled all CB plugins except:

CBSubs Eng-GB *language plugs cannot be disabled!
Default language (English)
Default
CB Articles (CB 2.x) * don’t have
Private Message System
CB Core
CB Menu
CB Connections
CB Forums (CB 2.x) * don’t have

Installed base packages CB & CBsubs, success reported.
Disabled and uninstalled all CB plugins flagged as "incompatible" ( there were half a dozen, including the GB language)
Re-enabled all CB plugins that were in original installation.

Testing… Still get 500 error when looking at a plan…
UNINSTALLED CB-GroupJive plugin… THIS SEEMS TO BE THE FIX!

So far, so good (no more 500 errors are apparent…) At this point it looks like I now have a successful migration.

Question!!
Is there a checklist of settings that will need to be re-configured after this migration?
Or do I need to manually go through the entire live installation and print out all existing 1.9.1 settings?
( and prior CBsubs settings)

A quick initial scan through the modules gives the appearance that it hasn't lost anything

I'd compare your configuration of your dev site to your live site.. GJ was probably causing that due to old APIs loading. Should've been enough to simply unpublish it though. When migrating do CB first and only CB. Best way actually is to unzip the package installer and install CB from extensions/packages/ so it skips the package installer when doing this migration just to be extra cautious, but if everything is fine now you can begin updating all your plans.

We only have the below video as to what you can expect with the migration.

Sorry, I don't quite understand what you mean by " unzip the package installer and install CB from extensions/packages/ "...

Whats wrong with just taking pkg_communitybuilder_2.0.14+build.2016.08.23.14.39.03.b6689b7c7.zip and uploading through the Joomla "Upload Package File"?

You are suggesting that I "Install from Folder"? ( Usually that's the /html/tmp folder... )?

"unzip the package installer" - to Where??

What do you mean by " install CB from extensions/packages" ?? I don't quite follow you...

When you download something from us it comes in a Joomla installer called Package Installer. We've reports of it not working so great during migration. To workaround this unzip it and you'll see a folder structure of extensions/packages/. Inside that folder is the actual CB package that package installer would be installing. Install that instead to skip using Package Installer.