das Upgrade
upgrade
The updating or improvement of a product, especially software or hardware, to a newer, more powerful version.
Das Upgrade auf das neue Betriebssystem ist kostenlos.
The upgrade to the new operating system is free.

upgrade
Loading your saved state.
upgrade
The updating or improvement of a product, especially software or hardware, to a newer, more powerful version.
Das Upgrade auf das neue Betriebssystem ist kostenlos.
The upgrade to the new operating system is free.

'Upgrade' is often combined with the verbs 'machen' (to do/make), 'durchführen' (to carry out), 'installieren' (to install, more for software), 'bekommen' (to get), or 'erhalten' (to receive, more for services).
Ich habe für mein Handy ein Software-Upgrade bekommen.
I got a software upgrade for my phone.
The preposition 'auf' (+ accusative) is used to name the new, better version. The preposition 'für' (+ accusative) describes what is being improved.
Das Upgrade auf die neue Version ist kostenpflichtig.
The upgrade to the new version requires payment.
You can easily recognize the meaning from context. If people are talking about computers, software, or phones, it means a technical update. If it's about flights, hotels, or tickets, it means an upgrade of the service.
Nach dem Upgrade startet mein Computer viel schneller.
After the upgrade, my computer starts much faster.
improvement / correction
'die Verbesserung' and 'das Upgrade' can both mean that something becomes better. 'Verbesserung' is the more general word and fits many areas, for example work, health, language, or technology. 'Upgrade' is used especially for technology, software, devices, or for a higher class of service, such as in a hotel or on a plane. When it is about a new, better version, 'Upgrade' sounds more natural. When you are simply saying in general that something has become better, 'Verbesserung' fits better.

Für das neue Programm braucht mein Laptop ein Upgrade.
My laptop needs an upgrade for the new program.
Hast du eine Verbesserung bei deiner Aussprache bemerkt?
Have you noticed an improvement in your pronunciation?