Refer to the following release notes for the major releases of DsPdf.   

• Release Notes for Version 6.2.0
• Release Notes for Version 6.1.0
• Release Notes for Version 6.0.0
• Release Notes for Version 5.2.0.800
• Release Notes for Version 5.1.0.790
• Release Notes for Version 5.0.0.762
• Release Notes for Version 4.2.0.719
• Release Notes for Version 4.2.0.715
• Release Notes for Version 4.1.0.658
• Release Notes for Version 4.0.0.616
• Release Notes for Version 3.2.0.548
• Release Notes for Version 3.1.0.508
• Release Notes for Version 3.0.0.414
• Release Notes for Version 2.2.0.310
• Release Notes for Version 2.1.0.260
• Release Notes for Version 2.0.0.200

For details about latest hot fixes, see the nuget page.