A/B Testing plugin let's you experiment with different variants of your remote configuration variables to find the best performing variant based on your goals. You can then roll-out the winning variant to all your users.
You can take advantage of all your default/custom user properties and user actions (such as sessions, views, custom events etc.) while building the target audience for your experiment.
Experiment goal definition in Countly A/B Testing is backed by Behavioral Cohorts plugin. Essentially, you can measure the affects of each different version of a remote configuration variable on increasing number of users that are in a cohort.
A/B Testing doesn't require an SDK update if you already use Remote Configuration inside your application.