SSIS packages created using SQL Server (2005-2017) cannot be automatically upgraded to a later version without first performing a pre-upgrade step. First, open the .dtsx package file in a text editor such as Notepad. Next, replace all instances of 126.96.36.199 (if created using SQL Server 2005), 10.0.0.0 (2008), or 188.8.131.52 (2012), or 184.108.40.206 (2014) with either 10.0.0.0 (if upgrading to SQL Server 2008), 220.127.116.11 (2012), or 18.104.22.168 (2014), or 22.214.171.124 (2016), 126.96.36.199 (2017), 188.8.131.52 (2019) then save the modified file. Lastly, open the solution with BIDS (2008) or SQL Server Data Tools (2012/2017/2019), which will automatically convert the solution and package.
Note that as of SQL Server 2014-2017, SQL Server Data Tools must be downloaded and installed separately; please refer to: https://docs.microsoft.com/en-us/sql/ssdt/download-sql-server-data-tools-ssdt?view=sql-server-ver15
For SQL Server 2019, please see this article Adding Data Tools/Integration Services to Visual Studio 2019
*2019 requires mSQL version 184.108.40.206 or newer
If you need to downgrade a project - then please click here