Thought better of the recent change to make "snap" no longer change

units;  although that is a more proper usage, it also happens to
break a lot of existing scripts.  Since virtually all of these
scripts start out with "snap internal" to force units, I have kept
this single usage, when "units" is still set to "default".  That
keeps the older scripts from breaking, while hopefully scripts get
updated over time to use "units" instead of "snap".  Note that there
are still ways to make this behavior break, such as running
"units microns" to set units and then sourcing a script that assumes
that "snap internal" will change the units, which will then not
happen.  But batch scripts should be handled property with backwards-
compatibility mode.

VERSION

@@ -1 +1 @@
-8.3.610
+8.3.611

commands/CmdRS.c

@@ -2900,6 +2900,29 @@ CmdSnap(
 	TxPrintf("Usage: snap [internal | lambda | user]\n");
 	return;
     }
+
+    /* Backwards compatibility:  Use of "snap" to set units display and
+     * parsing has been deprecated as of February 2026.  However, as this
+     * is rather disruptive to existing scripts which use "snap" to change
+     * the parsing of units, then the following measure is being taken
+     * (for now, anyway):  If DBWUnits is set to DBW_UNITS_DEFAULT, then
+     * "snap internal" will set DBWUnits as well as DBWSnapToGrid.  If
+     * DBWUnits is changed first (e.g., "units internal"), then "snap" will
+     * affect only the snap grid.  The older usage will be accompanied by a
+     * warning message.  Note that backwards compatibility is being kept
+     * only in the case of "snap internal", which was commonly used in
+     * scripts to make sure that all units were interpreted as internal
+     * units.
+     */
+    if ((DBWUnits == DBW_UNITS_DEFAULT) && (n == SNAP_INTERNAL))
+    {
+	DBWUnits = DBW_UNITS_INTERNAL;
+	TxError("Warning:  snap setting is also changing units.  This usage "
+		"is deprecated\nand may be removed in the future.  Use "
+		"\"units\" to change units, and\nchange units before "
+		"setting snap to keep this message from appearing.\n");
+    }
+
     switch (n)
     {
 	case SNAP_OFF: case SNAP_INTERNAL: