Salut Aminata,
We will need a bit more information about this error, your installation environment, and your upgrade process to be able to assist you. For example:
- What is the full version number of your 2.6 installation, as shown in Admin > Settings ?
- Are you following the recommended installation instructions for 2.8 (e.g. Ubuntu 20.04, PHP 7.4, Nginx, Elasticsearch 5.6, MySQL 8, etc), or are you making any changes? If you are making changes, tell us more about them
- Does your installation have any local customizations or code changes, including a custom theme plugin?
- Are you attempting to install the new version using Option 1 (install from our downloadable tarball) or Option 2 (install from our GitHub code repository) in the installation instructions?
- At exactly what step in the upgrade / installation process are you getting this error? The upgrade process generally involves installing a new version of AtoM alongside your old one first, and then copying in the data and running some tasks. Did you successfully get 2.8 installed, and are you encountering this error while trying to load your data? Or are you encountering this error while still trying to install 2.8?
Hopefully with more information, we will be able to offer you additional assistance!
Cheers,