The beta test of the new MetaTrader 4 version is currently underway.
The update's main features include changes in MQL4 programming language.
It has been substantially revised, and its functionality has been
brought closer to that of MQL5.
Of course, we have made every effort to ensure compatibility with
older MQL4 applications. However, some issues may still occasionally
occur. If you have encountered an error while compiling a new code,
please inform us in the appropriate thread of the official MQL4 forum.
We also urge you to pay special attention to the following points:
1) In the new build, the file structure for storing the source codes has changed. Previously, all MQL4 programs were stored in Program Files\<terminal_installation_folder>\ root directory. Now, they should be stored in Users\<data_folder>\MQL4\.
Thus, if a program has an absolute pathname for some file, you may run
into an error message in the compiler. To avoid this, specify a relative
pathname in the source code and re-compile it. The data folder can be
accessed via File -> Open Data Folder.
2) All old EX4 files will work correctly in the new terminal assuming
that they are not changed. In order to maintain compatibility, the
runtime environment copy of the previous MQL4 version has been
implemented providing operability of all older codes.
Good News ==D