The Simplicity Studio release that was made on Friday April 26th (SV188.8.131.52) had issues that prevented some Simplicity Studio installations from updating correctly. The installations that would fail were versions SV184.108.40.206 and SV220.127.116.11. If the last time Simplicity Studio was updated was before March 29th (so version SV18.104.22.168 or earlier) then the update worked correctly.
This issue has been resolved with the Simplicity Studio release that was made Tuesday afternoon, April 30th 2019 (UTC-06:00). The version of this release is SV22.214.171.124 (seen from [Help] > [About]). This release will update all versions of Simplicity Studio and it will fix any failed attempts to update to SV126.96.36.199. It will also properly update any installations that had worked around the update issue by manually applying an update to the Simplicity Studio Product package and then applying the other updates.
If Simplicity Studio is configured to automatically check for updates when it starts (the default setting) then the user will automatically be prompted to install the new update after they start or restart Simplicity Studio. If Simplicity Studio is configured to manually or periodically check for updates, then clicking the [Update Software] link will check for updates and then the available updates can be seen from the [Package Manager] [Product Updates] tab.
Depending on when Simplicity Studio was last updated several more updates could be available. To apply all of the available updates click the [Update] button and then after the update completes restart Simplicity Studio.
If any problems are seen with the update, please respond to this Knowledge Base Article or else create a new Simplicity Studio Community Forum thread or support case to report the issue.
Silicon Labs apologizes for the inconvenience this update issue has caused our customers.
I updated the new version of Studio V4 (SV41.10.0) follow your KBA, result is OK.
Thank for your support.