I already had some SNMP devices configured. But I can confirm that the Software menu option (usually between Config Properties and Custom Properties) is missing.
One thing to note is that I don't usually use that option, mainly as it's almost always blank. Maybe there's some new logic that won't show the option if there's nothing to show? In 4.2.3 under the Components menu (also on the left) some things like Cards and Processors won't appear if there's nothing to show. Or at least that's how it looks to me.