Unfortunately the update server is currently not working properly.
The update server normally provides update information for pimatic core and plugins and precompiled packages for the arm architecture to speed up the installation time of plugins.
Technical problems: The current problem is, that the update server uses npm search pimatic-
to receive a list of all plugins from the npm registry. However the npm registry is growing and npm runs out of memory at building a local index for the search.
I will report it here, when the problem is solved.