Multi-Version Client (MVC) was introduced to enable applications to work with FDB clusters of different versions and, in particular, to support FDB cluster upgrades. The current code of MVC theoretically supports the versions starting from 4.0. I say theoretically, because in practice we are currently testing interoperability with 6.3 or newer versions.
Removing support for 6.2 and older versions in 7.3 will enable cleaning up a lot of otherwise unnecessary legacy code. We would cleanup the MVC code and the API, i.e. fdb_c.h and bindings. 630 will be the lowest API version that can be selected.
One implication is that it won’t be possible to have an application connecting both to a 7.3 cluster and a 6.2 or older cluster. Another implication would be that it won’t be possible to upgrade to from a 6.2 cluster to a 7.3 without rebuilding and redeploying the application.
If you have any objections or concerns about this change, please let me know.