I had problems updating YAWL 4.0. The yawl control pannel show the messagge failed to donwload updates with the list of link to github (see attached image) , althougth i have no connection problem.
Do you have any solutions?

I have updated YAWL 4.0 today using the control panel without any problems. 

Have you tried reinstalling YAWL from scratch and try another update?

Yes I have tried different time. I have no idea what is wrong, coud it be the operative system or the java version? I use jdk1.8.0_91on windows 10.
For now I have installed manually the plugin, but following the manual I was able only to use the war of the version 3.
Thank you for the help.