Dolphin Smalltalk has been made open source following a long struggle to stay in the commercial sector. The source code is available for download on Github.
Before this move, Dolphin came in two versions; a free Community Edition and a commercial Professional Edition, both at version 6.
The new open source version has been named Dolphin 7, and is essentially equivalent to Professional Edition 6. Dolphin is a development IDE for Smalltalk targeted specifically at Windows. You can use it to create standalone GUI and console executables for versions of Windows from XP to 10.
A move to open source was first talked about in 2007. At that point the developers said they could no longer viably develop Dolphin into the future. One comment from the developers back then said they
"dislike the Open Source movement intensely and we would rather see Dolphin gradually disappear into the sands of time than instantly lose all commercial value in one fell swoop".
However, they also said they were happy to put the product into open source so long as they received some payment in recognition of the time and effort in developing the product.
The move to open source was announced in the company blog, where the post said:
This is a quick announcement to our blog subscribers to let you know that Dolphin Smalltalk is about to go open source. A new version, Dolphin 7, which is equivalent in function to the previous Dolphin Professional product will be released on the GitHub public source sharing repository later today.