Between releases, SPSS provides patches to fix known problems with the software. If you want to install these, you will first need to download them from the SPSS website and then install them.
You may also wish to update the extensions (user-written commands) that you have installed. To do this, you can click on Extensions and then Extension Hub. Click on Update Available (at the bottom of the column on the left), and then click Apply and follow the directions.