Apologies for being unclear. <Invoke> will still respect CheckStatus="false" or CheckStatus="0" by ignoring any returned statuses for that method. What has changed is the default behavior is to check the status, so perhaps deprecate is not exactly the right word here.

The issue has been fixed for IPM v0.10.5!

I've never tried with a custom buffer but I know you can redirect python stdout pretty easily using something like this:

sys.stdout = open('file', 'w')

Or this to completely suppress output:

sys.stdout = open(os.devnull, "w")

And then when you're done, use this to revert:

sys.stdout = sys.__stdout__