If your operating system does not support the latest version of the eBay app and you cannot update your operating system or use a previous version that is still supported, it should still be possible to use a mobile browser to go to ebay.com or ebay.co.uk and use eBay that way.
If you are using an older iOS version, see instructions here for installing a compatible version of the eBay app:
Previously that was working for iOS 15 users; not sure if things have changed recently.
If eBay browser links are opening in the app automatically, iOS users should be able to tap and hold an eBay browser link and select "don't open in the app" to prevent that from happening.
