Automatic folder config for Yahoo!, Gmail, and other RFC6154 SPECIAL-USE-compliant servers
Set the IMAP namespace for Gmail during auto-configuration
Changed UI to allow selecting the empty IMAP namespace
Set 'When I delete a message' to 'Delete from server' by default for IMAP on automatic setup like manual setup does
Set default names for Archive and Spam on manual config like automatic setup does
Added autoconfiguration settings for several providers
Options
Option to have confirmation on deleting starred messages
Option to strip signature from quoted text in replies
Extended setting to hide subject in notification area (never, when locked, always)
Save settings changes "on pause" rather than "on back" so we actually save settings when a user hits home or menu or whatever
Added font size setting for text input fields in the message composition screen
Added a setting to disable marking messages as read on viewing
Enable system zoom and disable gestures by default
Add discard confirmation dialog when pressing back in message compose
Option to now refuse to save drafts of messages marked as encrypted
Composing mail
Added a button to switch the identity in the message composition screen
Prompt user which email address to use when a contact with multiple email addresses was picked
Replying to mail
Fixed quoting of text/plain reply when sending text/html messages (builds plain reply separately instead of converting from the HTML)
Forwarded messages always use the quoting style 'Header'
You can now can have reply and signature before quote, reply and signature after quote, or reply before and signature after quote (setting reply after and signature before still corrects to both after)
Convert quote characters in plain text messages to blockquotes in the HTML version. "Be like Thunderbird."
Colorize quoted text that has been converted to HTML. Like Thunderbird, but optimized for mobile (no right margin quote bar, thinner left margin quote bar).
Added 'From:' addresses on "reply all" even when 'Reply-To:' is set. Don't repeat address in 'To:' field if it's already included because it's the 'Reply-To:' address.
Reading mail
Preserve header order (with the exception of duplicate headers like 'Received' they all show up where the first one did)
Improved zooming/scrolling when viewing a message
Added long-press popup menu to links in email message display
Workaround to detect the charset from HTML mail without charset parameter on the header
Added button to show unnamed and inline attachments
Message list
Added batch buttons for 'Archive' and 'Move'. Made batch buttons configurable
Remember the most recent sort setting in the message list
Added a "sort by arrival" option
Widget
Added widget to display the unread count for an account
Added launcher shortcuts for special accounts/folders ("Unified Inbox" and "All messages")
Protocol support
Fixed the parsing of response data for WebDAV requests
Fall back to HELO command if the server doesn't know EHLO (SMTP)
Improvements to mail sending timeout issues
Yahoo! IMAP seems to no longer require 'ID ("GUID" "1")' over non-3G. See http://mobile.yahoo.com/mail for IMAP setup instructions.
Platform compatibility
Support ACTION_SEND extras when handling ACTION_SENDTO. Too many applications get this wrong and rely on the undocumented behavior of the AOSP Email app and Gmail
Notable bug fixes
IMAP message UIDs are 32 bit unsigned values and cannot be stored in int, so we now parse them as long.
Disable special screen reader mode on ICS. The default message view has special accessibility features already.
Don't save to drafts if drafts folder is -NONE-
Hide buttons & settings that don't do anything on POP3 accounts
Delete attachment metadata and thumbnails when deleting attachments