This is the biggest update since the initial release!
Some major points of this release are:
Overall performance improvements.
Major overhaul of the single player AI logic. Additionally, users can optionally enable AI diagnostics on a game, and upload the game + diagnostics to address future any future issues or make improvements. AI logic is now also "versioned", so in the future, if major changes are made to AI logic, it might be possible to retain the old behavior if users prefer.
New with this version is the ability to play multiplayer games on a Local Area Network. No servers or online accounts needed! This is an add-on optional feature that can be purchased separately.
You can play against other human players using this or any other edition of Straight Up Poker version 1.5 or higher(*). This includes cross-platform game play, including the mobile version of Straight Up Poker (In open Beta on Android devices, and in the works for iOS).
Any player on desktop editions can host games, even custom game types are supported, the clients will download the game rules from the host on the fly, seamlessly.
This update was a six month effort. A large part of that effort was a lot of "behind the scenes" type stuff that isn't highly visible to end users, or they were subtle issues. One example is that the Anaconda game type was broken, blinds were not correctly handled. Another was that the game data export from replay could crash for certain combinations of game types and options. This is very very complex software developed by a very small team. In making this release, several internal-only features and tools were developed that is going to pay dividends in the future, as some of the tools help greatly with debugging and analyzing game play and AI units. Some of these internal features might even get promoted to the public versions of the software one day!
One important Note for this update, you must be on a recent version of the Steam Client, or the software won't run. This is true even if the 1.4 version of the software used to work with the older Steam client. If you have problems running the software, please check your steam client. I apologize if this causes inconvenience, but Steam doesn't support sticking to old versions of its client, and it's not feasible to maintain support for old Steam clients when Valve doesn't support that either.
(* Please note that each player needs to have their own licensed copy of the software to play on a LAN game. )