Why did Adobe do that?

[Cactus Cowboy]

How long was it between Adobe's release of ps 5.5 from ps 5.0. and what exactly was the difference or what issues did it address? Thank you for your answer in advance.

[c.pfaffenbichler · Accepted solution]

Photoshop 5.5 was released 1999 – are you sure you are talking about that?

Adobe Photoshop version history - Wikipedia

[Zaid Al Hilali]

There were no differences between them. Neither Illustrator, there was however a big difference in InDesign.

That was the only time Adobe released a .5 release in Creative Suite. It was the time when Adobe released Digital Publishing Suite as part of InDesign and didn't want to wait till next major release i.e CS6.

Actually Photoshop wasn't named 5.5, but 5.1