The message appeared in the MQL5 forum.
July 1, 2016 support for MetaTrader 4 terminal versions below 940 will end
Support for MetaTrader 4 terminal builds below 940 will be discontinued on July 1, 2016. Unsupported terminal builds will not be able to connect to the new server versions. Therefore, we strongly recommend that you upgrade your terminal.
From this point of view, the only supported releases would be 940, 950 and 970. While the 940 and 950 are compatible with each other, the 970 compiler produces script executables incompatible with predecessors. All script downloads in this site will be compiled by 950 compiler.
It also means that the 840 alternative versions of Ovo scripts become redundant and shall get removed from this site after the announcement date.