There is no specific preparation you need to do to upgrade to JExcel x.yz. However, if you are upgrading from any version below JExcel a.bc. it's very important that you follow the x.yz. preparation guide.
Upgrading from JExcel LITE or PRO (server) 1.11.6 to JExcel NEXT or JExcel DC:
Uninstall all the 3 modules of JExcel:
JExcel (or JExcel LITE)
JExcel Pro (or JExcel PRO)
Moresimp ActiveObjects Module
2. Reinstall the 1.11.6 version:
https://marketplace.atlassian.com/download/apps/1215293/version/101100600
(the link downloads it directly)
3. Uninstall the JExcel Pro module if it.
4. Install the LITE version latest (1.19.9):
https://marketplace.atlassian.com/download/apps/1213732/version/101610021
(the link downloads it directly)
5. Install the PRO version latest (1.19.9):
https://marketplace.atlassian.com/download/apps/1215293/version/101610020
(The link downloads it directly)
The new Moresimp ActiveObjects Module will automatically come with this version that you can keep.
6. Uninstall the JExcel LITE 1.16.1.
7. Keep using the JExcel PRO 1.16.1 with your old workbooks.
If it would not happen, please send us your Support ZIP.
This is how you can create it: https://confluence.atlassian.com/support/create-a-support-zip-790796819.html