The latest build has a lot of mechanics work in it. The spell system has a lot of improvement, and enchantments (buffs/debuffs) have been reworked, and a lot of new spells added. The mana cost for maintaining an enchantment grows exponentially if you add additional enchantments to a regiment. Researching enchantment magic techs increases the number of enchantments before increased upkeep kicks in.
A lot of regiment have been added tied to various research items, and the code for making spells and units depend on research and wizard traits. E.g. A faerie wizard researching lesser war magic will gain the ability to recruit the murderous Redcaps, in addition to the normal unlocks for this tech.
The world generation has also been improved so it is a bit faster and the cultural generation tweaked and improved for various generator paths.
The wizard tower expansions have also had work done, and more of them now unlock regiments.
Next update will feature a proper installer and an update-on-launch mechanism, so the game can be updated to the latest build without having to download manually from this page.
Download link: http://wizardsandwarlords.net/files/WizardsAndWarlords007b.zip.
WinXP users get .NET 4.0: http://www.microsoft.com/en-us/download/details.aspx?id=17851 instead of 4.5.1 (which is not compatible with XP).