At the beginning of the Rhapsody project at Apple, it was pretty easy to tell if you had some Rhapsody media... it just said "Rhapsody" on it. That changed when Apple started the Mac OS X project where they applied the Mac OS X (Server) name to Rhapsody when the first publicly available versions came out.

Still, none of the media (Rhapsody Developer Releases or Mac OS X Server releases) had the actual Rhapsody version numbers printed on the media. So identifying that takes installing Rhapsody to find out... or I could just tell you.

For the Developer Releases, the first Developer Release is Rhapsody 5.0 and the second (Developer Release 2) is Rhapsody 5.1. As stated earlier, these say Rhapsody right on the media so it saves some time.

The version numbers and code names for these versions can be seen below.

As mentioned in other places on this site, Apple canceled a planned release of Rhapsody as a workstation OS. Do to the gap in version numbers, and the fact that Apple was very close to the planned release at the time they canceled it, I think we can safely say that that version of Rhapsody (which never made it off Apple's campus) was Rhapsody 5.2.

Mac OS X Server media
Apple released Mac OS X Server in 1999. It appears to be the base Rhapsody OS with a suite of server related apps included (much like they would do with the Darwin-based Mac OS X Server versions later on). So it should be safe to assume that (minus the server stuff) this was what the workstation version of Rhapsody would have been like. Which in turn is a good thing as Mac OS X Server was the only way for web developers to work with WebObjects on Macs.

Mac OS X Server 1.0 is Rhapsody 5.3, the system displays the following information about itself in the console and terminal.

It wasn't long before Apple released an update. In the Server version numbers this update was 1.0-1 (or 1.0.1), but even though it was a small update, it included deep system changes which resulted in a new version number for Rhapsody, version 5.4. This is what the system displays for this version.

Apple later released a more extensive (and larger) update for Mac OS X Server. This was a combo update so it could be applied alone to the system without to having applied the first update. The Server version number given this update was 1.0-2 (or 1.0.2), and the new Rhapsody version new was 5.5. This is what the system displays for this version.

Mac OS X Server was only supposed to be around a short time until the real Mac OS X was finished. Well, Mac OS X was taking longer than expected (solving issues with Carbon). Apple was moving along with their hardware and had released new Power Mac G4 systems. Much like the developer released predating the G3, the current versions of Mac OS X Server at the time predated the G4.

Getting Rhapsody to work on the G4s required more than the standard update... and it required updating the installation CD. Apple released Mac OS X Server 1.2 to address the G4 compatibility problems. This was Rhapsody 5.6 and here is the system displays for this version information.

And even after extending the Rhapsody far beyond what they had envisioned, Apple had to do so yet again. Advances in the G4 line required more improvements to Mac OS X Server... but not at the core system level it would seem. The next version, 1.2 v3, was still Rhapsody 5.6, though the code name did change. Apple took this version a little further than many people generally know, it is able to be installed on the first rev of the eMacs which were released after Apple had stopped shipping Mac OS X Server.

Here is the display of the version information for the last version of Rhapsody.

The difference between Server 1.2 and 1.2 v3 can be seen on the CDs themselves (as displayed below).

Mac OS X Server 1.1
You may have noticed that I haven't brought up Server 1.1 or linked it to any version of Rhapsody. That is because Apple skipped that version... well, most of Apple did at any rate.

It appears that in a few of the later runs of the Mac OS X Server 1.0 CDs, version 1.1 was silkscreened on them. This is what apple had to say about it:
Note: This article pertains to Mac OS X Server versions 1.x, which were released prior to May 2001.

The Mac OS X Server CD with Part number Z691-2251-A identifies the software as version 1.1.

Affected Products
Mac OS X Server CD part number Z691-2251-A

The correct version number for this particular release is version 1.0.
And this is what the offending CD looked like.

But I have found out that someone else I know (Markus, who sent me the inset image) has a CD with 1.1 printed on it but is not one of the Z691-2251-A runs. His CD displays Z691-2308-A. I'm guessing Apple didn't catch this one when writing their tech notes on this.

So here is a table of all the versions of Rhapsody and their related code names and product names.
 OS Version OS Name OS Product Name OS Code Name
5.0 Rhapsody Rhapsody Developer Release Grail1Z4
5.1 Rhapsody Rhapsody Developer Release 2 Titan1U
5.2 Rhapsody Rhapsody 1.0  
5.3 Rhapsody Mac OS X Server 1.0 Hera1O9
5.4 Rhapsody Mac OS X Server 1.0.1 Hera1O9
5.5 Rhapsody Mac OS X Server 1.0.2 Hera1O9+Loki2G1
5.6 Rhapsody Mac OS X Server 1.2 Pele1Q10
5.6 Rhapsody Mac OS X Server 1.2 v3 Medusa1E3
As it is a little hard to find the updates on Apple's downloads site, I'm supplying these links to the North American versions. These require at least Mac OS X Server 1.0 (Rhapsody 5.3) and are not stand alone operating systems or updates that can be applied to any earlier versions.