vladv wrote:but of course the MQL5 will not be backward compatible with MQL4
If it of course won't be compatible,
then people won't upgrade to it or will try to revert back to MT4
(I need to save current download for MT4, just in case)
Good upgraded software must be backwards compatible
and have more new options & fixes.
There was an upgrade from MT3 to MT4 couple of years ago,
I don't know much about it, but there were some minor
problems with this upgrade.