WooCommerce 3.1 is on the way. After testing, all of our releases of our plugins are believed to be compatible. (WooCommerce now uses semantic versioning principles. 3.1 is intended to not add any backwards incompatibilities compared to 3.0; that would be indicated by a major version bump to 4.0. Hence, this result is as expected).
In accordance with our “one in, one out” policy, we will henceforth be providing support for our plugins for use with WooCommerce 2.3 onwards (so, the supported series are now 2.3, 2.4, 2.5, 2.6, 3.0 and 3.1). To be older than this, you’d have had to not updated your WooCommerce install since WooCommerce 2.2, released in 2014 – if that is where you are, it’s more than time for an update; but remember to test everything on a development copy of your site first!).