RDLC Report returns error after changing the report layout(Version issue)

I used to work on SQL server 2008 while working on the RDLC reports. Recently I have upgraded my VS and SQL server to 2017 and 2014 respectively. Now, My RDLC Reports run well if they are not edited. But If I need to change an Expression or Add a new column, On execution, I get the following error message:

    An error occurred during local report processing.
        The definition of the report 'C:\Users\Deepak\Documents\Projections\Projections\rptInvoice_Summary.rdlc' is invalid.
            The definition of this report is not valid or supported by this version of Reporting Services. The report definition may have been created with a later version of Reporting Services, or contain content that is not well-formed or not valid based on Reporting Services schemas. Details: The report definition has an invalid target namespace 'http://schemas.microsoft.com/sqlserver/reporting/2016/01/reportdefinition' which cannot be upgraded.

Can anyone help me how to fix this issue and get the report working with an ability to Edit or modify my reports.

 Please help me in this.

Regards,

Deepak