Thank you for writing back.
We have logged your request in our database under 2 tickets for feasibility analysis. The ticket details are available ahead. Please note, providing the support for PDF version 1.5 and 1.6 requires major changes to the API rendering core so we cannot commit the release schedule for these requirements at this moment. As soon as we have thoroughly analyzed the request on our end, and made significant progress towards achieving these features, we will post here to update you with the release schedule.
The ticket details are as follow.
CELLSJAVA-41132: Support for PDF version 1.5 for rendering spreadsheets to PDF.
CELLSJAVA-41133: Support for PDF version 1.6 for rendering spreadsheets to PDF.