I found a huge difference in currency value when I switched from ver 15.0.19 to ver 15.1.24. Now I opened the same file with both versions and could see the amount doubled in ver 15.0.24.
Could you please address this problem.
Your version is more than 60 updates behind. Try the latest version and see if the problem has been fixed.
There was a bug in how currency gains (losses) were calculated which was fixed in version 15.0.29. See Releases | Manager
This would explain why the amount is different after upgrade. The figure you see now is correct. The figure you saw before was incorrect.