If you have edited a file on your Bitrix24 drive and saved it, both the file itself and its previous version will be saved. You will be able to restore it in case there is an error in the new file. You may not need to restore the old file, but its version will be saved anyway and take up drive space. To automatically clean up space, unused versions of files will be automatically deleted after a certain number of days.
The number of days depends on your Bitrix24 plan.
Limits on the number of files and version storage time is applied to Bitrix24.Drive only. Versions of files used in Tasks, Feed, Calendar and CRM entities are stored indefinitely in all plans.
The maximum number of records in the document history is set on the Bitrix24 Settings Page.
Each version file is stored for 30 or 90 days, according to the plan, but provided that it has not been superseded by a new version of the file because of the limit in the settings.