The changelog is here: <a href="https://github.com/pharo-project/pharo-changelogs/blob/master/Pharo40ChangeLogs.md" rel="nofollow">https://github.com/pharo-project/pharo-changelogs/blob/maste...</a><p>Things that I find especially interesting, from new stuff:<p>> TxModel, a modern text model who works with Athens (Preview)<p>This is very, very nice. New text model was in the works for quite some time now and I'm glad it finally landed. Easy and powerful text editing is important, even in primarily GUI-driven environments. Pharo was a bit behind the times in this regard, which resulted in, for example, Shampoo (<a href="http://dmitrymatveev.co.uk/shampoo/" rel="nofollow">http://dmitrymatveev.co.uk/shampoo/</a>).<p>> OSWindow, a new way to handle windows and input events (Preview)<p>This allows for creating OS level windows from inside Pharo. IIRC it's supported only on Windows right now, but it's a very nice feature and will make creating apps that "look natively" easier.<p>> Slots model instance variables as first class enities and enable meta-programming on this level.<p>This looks rather important and I remember reading about it some time ago. There's a paper about it: <a href="http://scg.unibe.ch/archive/papers/Verw11bFlexibleObjectLayouts.pdf" rel="nofollow">http://scg.unibe.ch/archive/papers/Verw11bFlexibleObjectLayo...</a> - I'll need to read it again now that it's implemented.<p>Then there are updated things, all very nice too. Congratulations to the team and contributors!