Here's the changelog: http://irssi.org/news/ChangeLog

Features:

  * Document that SSL connections aren't properly handled during /UPGRADE. See Github PR #39.
  * Synchronize scripts with scripts.irssi.org.
  * Performance enhancement of the nicklist as well as the window_item_find function. See Github PR #24.
  * Disallow unloading of static modules.
  * Allow UTF-8 characters in /bind. See Github PR #18.
  * Split overlong outgoing messages instead of silently truncating them. Adds two new options: 'split_line_end' and 'split_line_start'. 'split_line_end' contains a string added to the end of line fragments. 'split_line_start' contains a string - added to the beginning of line fragments. See Github PR #29.
  * Added special /ignore NO_ACT level to ignore only activity (see /help ignore).
  * Support for 256 and true color terminals (see Github PR #48).
  * Support for italics (see Github PR #58).
  * Rewrote many help files.

Bugfixes:

  * Fixed various compiler warnings and use of deprecated functions.
  * Fixed Perl API usage and added PERL_NO_GET_CONTEXT to reduce code size.
  * Fixed format_get_text Perl API. See Github PR #23.
  * Fixed gui_printtext_after and term_refresh_*() visibility. See Github PR #22.
  * Fixed issue where UTF-8 characters was corrupted once for every 32k text. See Github PR #12.
  * Fixed redrawing issue with right-aligned statusbar.
  * Fixed use-after-free bug with cached settings values. See Github PR #147.

Slightly off-topic, but I really started to like WeeChat:

http://weechat.org/

Genuinely curious for those still using irssi; what can irssi do that weechat can't?

In my case, irssi is already installed, I have no real issues with it, and if I reviewed every time someone created an alternative to a program I use I'd never get anything done (not that I get anything done now, but one can dream).

Use less memory, which is good on memory limited shell accounts.

Does anyone have a screenshot showing off the truecolor support?