My question is should I install the latest free version as I now only use it for personal reasons or will the existing licence stop the backup from restoring? In which case what is the correct version to install given my licence?
If you have the latest Windows 11 or Mac Tahoe yes I would install the new V10 or you could find some things may not work properly.
You can normally restore a version 7 backup directly into version 10. The database will normally automatically upgrade your older version 7 database files to the modern database format during the restore process
So as you are now no longer operating a business and only want eM Client for non business personal use, then you would just need to activate eM Client V10 either with a “new free license” connected to a personal non business email address or “a paid personal license” connected to a personal non business email address depending on if you want to be able to use the full features of V10 with unlimited accounts or only two accounts & limited features.
“Choose your eM Client license” free or paid
https://www.emclient.com/pricing
So you would download and install the latest official V10 via the following page, and once installed, “skip the setup” and restore your V7 backup.zip via “Menu / File / Restore” and select your latest backup.zip file if you have more than one backup.zip file. By default the backup.zip file/s normally go in your “Documents / eM Client” folder.
Then once your V7 backup is restored, go to “Menu / Help / License” and deactivate your old restored business license, and then enter your new V10 free or paid personal license key and activate it.
Alternatively you could first install the latest V7 from the release history page for Pc or Mac and then “skip the setup” and restore your backup.zip file via “Menu / File / Restore”.
Then once restored go to “Menu / File / Export” and choose Export emails to .eml files. Then click next and “select your account mail folders” you want to export and “select your export folder location” & export.
Export (.eml) message files
https://www.emclient.com/webdocumentation/en/10.3/eMClient/Default.htm#Getting%20Started/Export/Export%20E-mails%20to%20.eml%20files.htm
Then once all your messages are exported, uninstall eM Client V7 and if you have Windows “delete the database” when asked on the uninstall wizard. If you have Mac then after uninstalling, “go to the following hidden database folder” and rename it to eg: eM Client-Old.
(Hidden database folder Mac)
/Users/User Name/Library/Application Support/eM Client
Then download and install V10 from the following page, and “setup your all accounts etc as new”. Next once setup go to “Menu / Help / License” and enter your V10 free or paid personal license and activate.
Then go to “Menu / File / Import” and select “Email (.eml) and click next and “select your exported message folder” and “account folder” where you want the messages imported to. Then click Finish to complete the import process.
Import (.eml) message files
https://www.emclient.com/webdocumentation/en/10.3/eMClient/Default.htm#Getting%20Started/Import/Import%20from%20.eml%20file.htm