ProBuilder Compatibility Issues After Unity Upgrade

Unity versions: Upgraded from 2020.3.0f1 to 2023.2.0

ProBuilder versions: Using ProBuilder 4.2.3 in both Unity versions

Copied objects lose mesh: Objects created in ProBuilder in 2020.3.0f1 lose their mesh and become invisible when copied into the 2023.2.0 project.

Export failure: Objects created in ProBuilder 4.2.3 in 2020.3.0f1 do not export correctly in the new Unity version. They do not appear at the chosen save location.

Vertex/edge/polygon editing not working: Unable to select or edit vertices, edges, or polygons of ProBuilder objects created in 2020.3.0f1 within the 2023.2.0 project. The editing mode appears to not engage.

New objects work fine: New objects created with ProBuilder 4.2.3 in the 2023.2.0 project function as expected.

ProBuilder 5.2 issue: When ProBuilder 5.2 is installed in Unity 2023.2.0, all objects created in ProBuilder in 2020.3.0f1 lose their mesh.

Would really appreciate if someone could advise how can make my objects created with older ProBuilder in older Unity version operational.

Thanks in advance