Sergei Vitalievich,
there are two OneBox tariff lines -
https://crm-onebox.com/en/prices/Box rates
The software is installed on your server, you serve it yourself.
Updates are paid.
Direct analogy: you bought windows and put it on your computer when a new version came out - you buy a new one at a discount if you want.
Cloud rates
The software is installed on our cloud servers, we serve them ourselves.
You are always on the latest version, you pay nothing extra for updates.
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Judging by your question, you have a cloud plan, so you don't have to worry about updates.