TGM Plugin Activation is a PHP library that allows you to easily require or recommend plugins for your WordPress themes (and plugins). It allows your users to install, update and even automatically activate plugins in singular or bulk fashion using native WordPress classes, functions and interfaces. You can reference bundled plugins, plugins from the WordPress Plugin Repository or even plugins hosted elsewhere on the internet.
Hi Thomas, I expect v 2.6.0 should be ready for release round the same time. In that case, this is already covered in PR #461 which will be updated still for the actual release.
The latest "Tested up to" says 4.2.0. With 4.5 coming out soon, we should go ahead and bump this to 4.5 (assuming everything functions as expected).