When you select a drafting standard, AutoCAD Mechanical toolset uses a set of symbols that comply with the standard.
You can perform the following additional configuration operations:
In general, if you modify the settings of a symbol during a drawing session, all existing symbols update. However, if you change the drafting standard (or the revision) in the middle of a drawing session, and then change symbol settings, only the symbols you created after changing the standard update. Symbols that you created before changing standards do not update, since they are not based on the current drafting standard.
If you save a drawing containing symbols to an older version of AutoCAD Mechanical toolset that does not support the options you have used, AutoCAD Mechanical toolset may convert the symbols to blocks in order to maintain visual fidelity. However, if you limit configuration to overriding the master text or leader settings, the symbols do not convert to blocks. Instead, the text and leader overrides are reset to the master settings.