Perhaps this belongs in "Installation" - but thought I'd share that I'm very confused by how 6A and MTOS are talking about Motion and Action Streams being "built-in" to 4.25.
Just upgraded to MT4.25 from MT4.23. For the most part, things went swimmingly, but my Action Streams widgets wouldn't publish -- system didn't recognize any of the AS tags. I didn't see an AS folder in plugins, but since movabletype.com says that Motion is built into 4.25, I thought maybe it had moved to unmarked core code. Finally I realized I was missing the plugin.
Here's what I did: 6A says clearly on the motion page "If you already use Movable Type Pro or Enterprise, version 4.25 is in your account. Sign in to your account to download." I did that. The only package in my account is called "Movable Type 4.25, with Pro Pack, Personal Use License", unpacks to MTCOM-4.25-en. This is the version that lacks Action Streams etc. in the plugins folder.
I finally followed a different download link to get a package called MT-4.25-en, and there I see a bunch of different stuff in the plugins folder - ActionStreams, CommunityActionStreams, FacebookCommenters, and mixiComment.
So, if I copy these four folders into the plugins directory in my MTCOM install, am I good to go? Or am I going to be missing bits in extlib, etc.? What version of MT is going to give me less trouble?
thanks in advance,
Jason
Reported on Movable Type 4.2

Did you have what used to be called a 'ProNet' version?
Thx for the fast reply, Rob.
To be honest, I don't know what kind of version I have/had. I know that I did shell out some cash in order to get Custom Fields functionality, back when that wasn't available in the free version.
How many different versions of MT 4.25 are there, exactly?
FWIW, I also discovered another difference -- the entire Community Pack wasn't in my MTCOM binary, either.
Again, I'm mostly bringing this up for 6A to note that their messaging to users about how to install Motion is misleading (http://movabletype.com/motion/ says to just sign in and download, which clearly didn't work for me). Though it would also be reassuring to know that I've got all the pieces I need -- having added back in the Community Pack and 4 additional plugins described above.
Anybody from 6A listening here?
-J
I have:
Movable Type Pro version 4.25 with: Community Pack 1.62, Professional Pack 1.3 and I'm unable to get any RSS, Atom content to display with plugins or via manual MTINCLUDE.
I had the same problem, solution was:
* Backup everything
* Move the old 'mt' directory to 'mt-old'
* Use the Unix 'diff' command to compare the two directories
* Copy the missing files (e.g., mt-cp.cgi) and missing directories (e.g., 'addons' etc.) to the new 'mt' directory
* Copy the missing plugins, or download them again, to the new 'mt' location
All is working a-ok now.
Phillip.
Oh, and, don't forget the stuff in 'mt-static/plugins/' either. ;-)
I'm in the exact same boat as Jason. I've been a long time MT user (2.x) and paid for custom fields. My "about" line reads Movable Type Commercial version 4.25 with: Professional Pack 1.3
My solution for getting Motion working was:
1) download MT Pro package from MT.com
2) copy Community.pack into existing /mt/addons/
3) copy mt-cp.cgi into /mt/
4) replace mt-static folder from existing install with MT Pro mt-static folder
5) replace plugins folder from existing install with MT Pro plugins folder
Seems to have added missing functionality. What a PITA this is going to be as they upgrade!