BioStar 2 supports direct upgrade from the v2.5 to the BioStar v2.6.x or v2.7.x. (You cannot upgrade from v2.5 to v2.8.x directly.) If you want to upgrade to BioStar 2 v2.8.x when using BioStar 2 v2.5, you should upgrade to BioStar 2 v2.6.x or v2.7.x at first. (Relevant article)
However, you cannot upgrade from a very old version such as v2.0 to v2.4 in one upgrade because that the process is not supported.
If you are upgrading from lower than BioStar v2.5, please refer to the following article to take a note of the upgrading process policies.
Below process contains re-installation process of BioStar 2 v2.5.
If you need to do upgrading only, please follow from Step 6.
Step 1 > Please make sure you have backup database, enckey, and other backup data from v2.5.
You need to restore pure database and backup items from v2.5, not the v2.5 -> v2.7 -> v2.5(rollback) one.
Please check you have backup items as attached link.
If you use Maria DB > [BioStar 2] Database Backup and Restore Instructions (Maria DB)
If you use MS SQL > [BioStar 2] MSSQL Database Backup and Restore Instructions
Step 2> Remove BioStar v2.7 from Control Panel.
You need to delete all data and reboot the PC.
Step 3> Install BioStar v2.5.
Step 4> Stop BioStar 2 server and restore your backup database and enckey file from BioStar v2.5.
Restore instructions are included at the Step 1.
Step 5> Check BioStar v2.5 restore is successful.
Step 6> As the license policy has been changed, please refer a below article and check your current BioStar 2 needs a new license.
If you need a new license, please contact Suprema representatives.
Step 7> Stop BioStar 2 server.
In this point, you must not uninstall BioStar 2 v2.5.
Step 8> Download BioStar v2.7 installation file and run to upgrade.
If you are upgrading from BioStar v2.5 and received a new license already, please choose ‘Manual license input’ and input the license number which you received from Suprema.
If you are upgrading from over BioStar v2.6 and already have a license as a file, please choose ‘Choose license file’ and adjust your license file for your upgrading.
Step 9> Check BioStar v2.7 upgrade is successful.