Rigol Technologies

Although Released firmware is designed to either correct or enhanced various features of an instrument there is always the possibility of the unexpected or that the "Correction" has changed how the instrument works in a particular application or situation.   Without a known limitation or identified issue, firmware upgrades are not always recommended.
The instrument system information may refer to firmware as software.
Here are the latest release notes.
The upgraded firmware for a DS1Z Series Scope can be downloaded from here

This firmware is applicable to all DS1000Z, DS1000Z-S, MSO1000Z, and MSO1000Z-S series scopes.
Here is the link to the procedure for getting this firmware into a DS1Z is:
Here are the release notes 
More information on the DS1Z Scope (data sheets, user manuals, programming manuals, FAQ's and programming examples) is at:
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