Yes it is true. It's was announced last November (quietly) during the changes to the Flex SDK and Flash Builder. I was disappointed. I had hoped that we would have seen an update to get the app in sync with the 4.6 release, but alas...
Unfortunately, FC is built to work with the Flex SDK, so it can't transform itself to an HTML5 tool. Adobe would need to start from square one to develop a HTML5 based FC tool.
I too am dissapointed that Catalyst has been dropped. I purchased a couple of books to help me on my way and spent some time trying to master this small application. However, there were many limitations with it and some of the important features I wanted were not there. At the end of the day I still have my current version which works and is still usable, so no hard done by feelings from me. I guess I will just have to wade through my 900 page manual on Flash Pro and learn that application.