Going by history, it may be a very very looong time before AT&T Wireless lets HTC create a distribution for the 8525 (AKA HTC TyTN) seeing as they only released a 6.0 version on Halloween this past year.

Get a look at the feature comparison of the different versions from the Windows Mobile 6.1 site after the jump.

The following comes straight from Microsoft site for WM6.1:

Feature	Windows Mobile 5.0		Windows Mobile 6.0		Windows Mobile 6.1		Description
	Non-Touch Screen	Touch Screen	Non-Touch Screen	Touch Screen	Non-Touch Screen	Touch Screen
Ease of Use
Getting Started Center					X	X	Get help setting up your new phone—from e-mail to a Bluetooth headset, so you can start using it right away.
Sliding Panel Home Screen					X		The home screen has a whole new look. View notifications and calendar appointments. Go straight to the Getting Started Center and settings. Listen to your favorite music and view your favorite photos.
Windows Default Home Screen	X		X		X		Get the look you want, including themes, colors, and wallpaper.
Today Home Screen		X		X		X	View notifications and calendar appointments. Access the Getting Started Center and lock your touch screen.
Mobile Messaging
Threaded Text Messaging					X	X	When you text with a friend or colleague, the messages are threaded together into a single conversation, so you can view the entire conversation as you type.
Exchange Server AutoDiscovery					X	X	The E-Mail Setup Wizard takes you directly to the Exchange ActiveSync e-mail setup so you can start getting your work e-mail on your phone.
Custom Domain E-Mail Setup					X	X	Want to get your e-mail from your custom domain in Outlook Mobile? Now the E-Mail Setup Wizard helps you set it up, step-by-step.
E-Mail Setup Wizard			X	X	X	X	Receive your e-mail in Outlook E-Mail. Now it’s easier to find and set up e-mail messaging settings for e-mail service providers, including Gmail, AOL, and Yahoo!.
Auto-Complete for Recipients		X		X	X	X	Want to send an e-mail but don’t remember the address or want to wade through past mail to find it? Just type a few letters of the name, and view the nearest matches in a drop-down menu.
Direct Push E-Mail for Exchange	X3	X3	X	X	X	X	See your messages as soon as they arrive from the e-mail server without performing a manual or scheduled Send/Receive. (Available for Microsoft Exchange 2003 SP2 and Exchange 2007.)6
Direct Push E-Mail for Windows Live Hotmail			X	X	X	X	View Windows Live Hotmail messages as soon as they arrive from the e-mail server without performing a manual or scheduled Send/Receive.6
Exchange Server E-Mail Search			X	X	X	X	Search e-mail by specific words, subject matter, and more.1
HTML E-Mail Support			X	X	X	X	Mail shows up on your smartphone just like it does on your PC—with all the colors, photos, and formatting. Receive, view, write, and send e-mail in HTML format (for Exchange 2007, Hotmail, and POP/IMAP accounts like Gmail, AOL, and Yahoo!).
Fetch Mail			X	X	X	X	Download an entire message, including inline images and attachments—without having to do a full Send/Receive.1
Fetch Mail for POP3/IMAP					X	X	If you use a POP3/IMAP e-mail account (like Gmail, AOL, or Yahoo!), you can use Fetch to download an entire large e-mail in with no additional intervention required.
SharePoint and UNC File Share Access			X	X	X	X	Open links to documents that are stored on servers or linked to in an e-mail.1
Outlook E-Mail Message Flags			X	X	X	X	Assign, mark complete, and clear flags both from the e-mail inbox list and when you’re viewing a message.1
Smart Filter in Messaging			X	X	X	X	Search for a specific message by entering a name or subject. Smart filter automatically sorts the list of messages based on the search criteria.
Hardware Shortcuts			X	X	X	X	Perform a variety of tasks, such as moving a message to a folder or flagging a message, on both 12-key and QWERTY (traditional Western keyboard) smartphone.
Information Rights Management			X	X	X	X	Receive, reply to, forward, and compose Information Rights Management (IRM) protected mail—confidential e-mails, read-only documents, and documents with an expiration date.1
Multi-Select Functionality		X		X	X	X	Select a block of messages for bulk actions, such as deleting or moving the messages.
Contacts, Calendar, and Tasks
View Attendee Status			X	X	X	X	See who has accepted, declined, or not yet responded to a meeting invitation.1
Forward Appointments			X	X	X	X	Forward appointments to additional meeting attendees right from your smartphone.1
Out-of-Office Assistant			X	X	X	X	If you’re going to be away from your office or out of cell phone range (maybe hiking or skiing), set an Out-of-Office (OOF) status and message.1
Propose a New Meeting			X	X	X	X	Respond to a meeting invitation by proposing a new meeting time.1
Schedule Conflict Notification			X	X	X	X	View conflicting appointments and appointments that are adjacent to the meeting request.
Call History by Contact			X	X	X	X	View past call history, including calls made, received, and missed.
Schedule New Meetings		X	X	X	X	X	Send meeting requests from your smartphone.1
Smart Search	X		X	X	X	X	Type a name or phone number and sort through your contacts until you find the right one.
Tasks Synchronization	X	X	X	X	X	X	Synchronize your Outlook Tasks so that you can stay on top of what’s important.
Internet Explorer Mobile
Zoom Support					X	X	Zoom in on a Web page to view small text or images.
Page Overview					X	X	View an entire Web page at one time, navigate to a specific segment, and then select that segment for a closer view.
Home Page Personalization		X		X	X	X	Select a custom Web page to appear as the home page you first see when you launch Internet Explorer Mobile.
Productivity
Cut, Copy, and Paste		X		X	X	X	Select and copy text from Web pages in Internet Explorer Mobile. And cut, copy, and paste text in e-mail and messaging.
Windows Live			X	X	X	X	Get the best. Windows Live is the premier service offering that unifies Windows Live Search, Windows Live Messenger, Windows Live Hotmail, and Windows Live Spaces.2
Windows Mobile Marketplace			X	X	X	X	Go shopping. View an entire catalog of software and other content developed by distributors, and then download the new content straight to your phone.2
Microsoft Office Mobile		X	X	X	X5	X5	View and edit Microsoft Office Mobile software, such as Mobile Word and Mobile Excel documents. You can also view Mobile PowerPoint presentations.2 4
OneNote Mobile	X4	X4	X4	X4	X	X	Take notes on your phone, and then synchronize the notes to the full version of Microsoft Office Mobile OneNote on a computer. You can get Mobile OneNote free with the full version of Office OneNote 2007 for PCs.
Live Search	X	X	X	X	X2	X2	Get this free application to view current traffic conditions, find directions, locate nearby restaurants, and more.4
Pocket MSN	X	X					Sign on from your Pocket MSN software and go immediately to your favorite MSN services such as Windows Live Hotmail, Windows Live Messenger, and mobile Web content.
Windows Media Player Mobile
Smart Search			X	X	X	X	Start typing a song or artist name and sort through music and videos until you find the right one.
Sync Digital Media	X	X	X	X	X	X	Synchronize digital media files to a device with ease using Windows Media Player on a PC.
Drag and Drop to Memory Card Storage	X	X	X	X	X	X	Easily load files onto a memory card to create a mobile library of your favorite media files.
Rate Favorites			X	X	X	X	Give each media file on your device a rating from 1 to 5 stars, and retain the settings when you sync it back to your PC.
Home Screen Integration					X		Music stored on your device can be played and paused from your home screen.
Pictures and Videos
Snap and Send	X	X	X	X	X	X	Easily share pictures you take with your device using e-mail or MMS.
Roll Camera	X	X	X	X	X	X	Take full-motion video with sound on your device to capture a moment.
Sync Pictures			X	X	X	X	With Windows Mobile Device Center (Windows Vista), your PC automatically detects new pictures when connected to easily tag pictures when syncing.
Make a Slide Show	X	X	X	X	X	X	Set your home screen to a picture you have taken, upload pictures to the Web, and more.
Send to Live Spaces			X	X	X	X	Devices with Windows Live are able to sync pictures seamlessly to a Windows Live Space.
Photos on Home Screen					X		Photos stored on your device can be viewed from your home screen.
Utilities
Remote Desktop		X		X2	X2	X2	Gain secure, remote access to Microsoft Windows personal computers and Microsoft server products.
Windows Mobile Update			X	X	X	X	Help keep your Windows Mobile smartphone more secure and fully up to date.
Set Multiple Alarms		X		X	X	X	Set multiple alarms on your device. Set a specific alarm to wake you up, remind you of a meeting or appointment, or alert you to task deadlines.
Voice Command		X	X	X	X	X	Use your voice. Launch programs, make a call, listen to your next appointments, and more with voice-activated commands.2
Voice Notes	X	X	X	X	X	X	Record a brief audio clip to capture an idea or send the note as a message attachment.
Bluetooth
Phone Book Access Profile					X	X	Allow your Bluetooth-enabled car kits to access phone book information.
Auto-Pairing of Headset					X	X	Automatically pair (connect) Bluetooth headphones or a headset to your smartphone—you no longer need to know the pairing code.
Advanced Audio Distribution Profile (A2DP)	X3	X3	X	X	X	X	Listen to your stereo through your Bluetooth headphones.
Connectivity
Internet Sharing			X	X	X	X	If you’re connected to the Web with your smartphone, but don’t have a Web connection with your laptop or PC, your computer can share your phone’s Internet connection. Using a USB or Bluetooth, it takes only a couple of clicks.2
Platform Management
Microsoft System Center Mobile Device Manager 2008					X	X	Active Directory/Group Policy—the most widely deployed enterprise network directory in the world—allows IT professionals to set and control policies in a single, familiar environment.