Downgrade steps:
a. Change the current xmlns to an old one
- Original SSRS xmlns = “http://schemas.microsoft.com/sqlserver/reporting/2016/01/reportdefinition”
- Older version SSRS xmlns= “http://schemas.microsoft.com/sqlserver/reporting/2008/01/reportdefinition”
b. Delete the “ReportSections” and “ReportSection” opening and closing tags (not the content)
c. Delete the entire “ReportParametersLayout” block
d. Delete PageName (of a Tablix) from the entire namespace, this line for example:
<PageName>Worksheet Name A</PageName>
e. Open the report again then select the Tablix and open its properties then re-input the name of the page in PageName