Indeed. It's hard to overstate how important a moment this is. It's still sinking in. It really means the end of VistA as a commercial system in the US, as they had the most success deploying it, reaching at one point 20-30 separate systems. (It's ironic though... because the founders of Medsphere did not initially want to target a US market.) A short history; I have this information from talking to lots of people over the last two decades. I am sure I have some of this wrong.
Medsphere was the first company that commercialized VistA and made it possible for hospitals to implement VistA without having to hire their own programmers. It was formed about 2005 by the Shreeve brothers. They set it up using a classic Silicon Valley funding model: Venture Capital. I was told their dream was to deploy VistA in South America, and they hired the people to do that. They did not intend their main market to be the US. They achieved their first success by having Midland Memorial Hospital in Midland, TX be one of the first non-Government/non-State hospitals to implement VistA. In fact, my first VistA Community Meeting was in Midland, TX, and I got a tour of the hospital. In the end, they couldn't really break into South America.
Around 2008, the investors thought that the company is not profitable enough and pushed the Shreeve brothers out (I never spoke to the Shreeves, so I am just relating hearsay on what the reasons they left the company are). Around that time as well, there was a big exodus of employees who left for other companies as they didn't like the change of management and direction of the company. (That part I can confirm personally, as I spoke to several of the people who left.) Up to 2008, the company seemed to be trying to do open-source; but I know that claim is hotly disputed here... so it was my impression anyways. After that, they went closed source.
On the tech stack, the most important change from classic VistA is after their acquisition of Clinical Informatics Associates (CIA), which created VueCentric. They took VueCentric and rebranded it "CareVue", replacing CPRS.
Also after the acquisition of CIA, who had an existing contract with IHS, Medsphere moved more in the direction of doing government contracts, both for IHS and VA.
I know George Timson will be mad at me if I don't mention their important contribution for modernizing Fileman, which is an important behind the scenes change. The Shreeves hired George to do needed changes for VistA, and not just in Fileman. For example, VistA did not have a good way to record that a patient was accessed for HIPAA compliance. MSC Fileman got that capability. MSC Fileman eventually got into the VA as part of the Fileman 22.2 project, which I was involved in.
Last couple of years, long time Medsphere employees were being let go. I figured something was happening.
--Sam