One of my readers tried to implement my OSPF Best Practices and found out that ...
The ip ospf area does not work on all platforms/IOS versions. I noticed that it works on 7600s(12.2SRB4), but not on 7200(12.2(23)). Is it IOS/platform specific or a newly introduced command?
There are two reasonably accurate ways to figure out which IOS release contains the command you're interested in: the Feature Navigator and the IOS reference documentation.
It's sometimes hard to discover how the IOS marketing called the feature implementing your command, so the IOS reference manuals usually yield a faster answer. However, you still have to select the correct reference manual to open ... unless you use the Command Lookup Tool, which quickly finds the relevant part of the documentation. In my case, I easily figured out that the ip ospf area command became available in 12.0S, 12.3T (and therefore 12.4), 12.2SB and 12.2SRB.
To add icing to the cake, you can add the Command Lookup Tool to your browser’s search toolbar.