Good question. There is currently no published timeline for phasing out support for v2. The current state of v2 is maintenance only -- all feature development is targeted at v3 now, and no new functionality will be added to v2.
We will, however, continue to provide support for v2 and fix any bugs in v2 as they are reported until further notice. We will provide a minimum of 6 months' notice, published both on our web site and in the "news" section of the Centova Cast control panel itself, prior to discontinuing support or maintenance for v2.
In practical terms, we don't intend to abandon v2 at any point in the imminent future, as a substantial portion of our client base is still using v2. When our licensing records indicate that a substantialmajority of our clients have moved to v3, we'll begin making (and publishing) plans to phase out v2.