We have identified some issues with the latest OS and will be releasing a fix shortly. The issues you may face after updating your OS are as follows:
.Delays when opening app/notebooks/closing notebooks
.Fonts are not accessible
.Text box can't be moved
The fixed version should be out within the next 2 business days (by 22nd Sep). If you have any concerns, please write to support via in-app Gear icon->Support->Contact Us->Send Email option.