Microsoft is removing the client and server keywords from X++.

I saw the announcement from Michael Landin last week and I think a lot of teams will miss it.

In 10.0.48 the compiler gives a warning when it finds these keywords. In 10.0.50 the warning becomes an error and your build fails.

The keywords have done nothing for years because the runtime ignores them. They are left over from the AX 2012 days, when it mattered where a method ran.

The fix is to delete the word.

public client static void myMethod()

becomes

public static void myMethod()

The method behaves the same as before.

Where I would look first is code that was migrated from AX 2012. New code rarely has these keywords, but old code often does. If you compile ISV source code in your build, check that too, and ask the vendor for a fix before you plan the 10.0.50 update.

A search across your models takes a few minutes. I would do it now while it is still only a warning.