When transitioning to a newer numbered version of 4D (E.G. 17 to 18, 18 to 19, etc), it is recommended to check whether the upgraded database has any obsolete commands. One way to check is to go into the Design mode menu bar Edit > Find in Design and search for the prefix "_O_" to see whether any instances of obsolete commands are found.

To check whether there is any substitute command, double click on one of the found instances to open the method editor, click on the obsolete command then hit F1 to open the documentation. Here the docs will note whether there is a substitute command or the command has been fully deprecated.