Welcome to the KNIME Forum! From which have you updated?
1 - This pop up window looks to just contains warning that seem to be non-fatal, can you still open and run the workflow?
2 - When your KNIME Server hangs, could you please extract a JSTACK? This will help us to figure it out what could be happening that causes it to hang. Also, how big is the file you are trying to read, and how much memory you have assigned to KNIME? (you can check this with the KNIME.ini file, in the -xmx parameter)
An explanation about how to extract a jstack can be found here: Knime Hangs during execution - #2 by AlexanderFillbrunn
cheers
Ana