These seemed to be working, then I updated R, Rstudio, and all packages... now, addins that require a shiny-interactive popup, appear to not be working. The app opens, but is blank (others that, say, just add in a bit of code, are fine).
In fact, even the window that allows me to "browse add ins" is doing this.
This error appears in the console:
Listening on http://127.0.0.1:5801
Error in .Call("_later_execCallbacks", PACKAGE = "later", timeoutSecs, :
Incorrect number of arguments (2), expecting 1 for '_later_execCallbacks'