Me once again .....
Yes, you must save the session and after reboot you can uninstall the older kernel if you want.
How to? Removing the old one ?Is this correct ?:
apt-get purge linux-image-4.4.0-112-generic linux-image-extra-4.4.0-59-generic
Can it be done also with Bleachbit ?
Thanks rcrsn51 for the Advice !