Update...in the Fiji main window.
Manage update sitesand deactivate the SciView update site by removing the tick mark.
Apply changesin the updater window. The release version of sciview will now be removed.
Apply changes, then repeat the steps up to here.
Manage update sitesand in the update site window, click the
Add update sitebutton. A new, empty list entry will appear. In the first column, enter
sciview-buttercup, and in the second column
https://sites.imagej.net/sciview-buttercup/. The URL is case-sensitive. Then activate the newly added update site by clicking the checkbox in front of the line you just added:
Apply changes, then Fiji will download the latest development version of sciview.