Welcome to the new world of "compatibility".
"The new opportunities offered by the updated MetaTrader 4 make it unreasonable to stay with older versions of the terminal."
The lack of ability to compile older programs is a good enough reason. In this situation there will be no chance to even
try anything older than 8 months. Besides there is no free reprogramming service of broken compatibility issues.
I still did not find any advantage of the programs rewritten and/or recompiled with the new builds.
More memory consumption, same speed.
As a developer I don't remember such a scandalous upgrade in the last 20 years as the release of build 600.
230769
MetaTrader 4 was officially released as far back as in July 2005 and went on to become the most popular trading platform in the world. More than 2000 MT4 servers are currently available to traders. Success did not come immediately, of course. It was obtained as a result of constant hard work while we were implementing more and more features and fixing user-reported errors.
In order to provide further development and implement new sought-after services, we decided to radically update MetaTrader 4 and concentrated all our efforts on complete rewriting of many critical components in summer 2013. It was a challenging task, but the result was worth it: MetaTrader 4 build 600 containing the fully updated client terminal with the new MQL4 language and the Market of applications was released on February 3, 2014. This was followed by the explosive growth in the number of trading applications uploaded to MetaTrader AppStore - the store of MetaTrader trading robots and indicators.
The new opportunities offered by the updated MetaTrader 4 make it unreasonable to stay with older versions of the terminal.