Having set the solution and project to dotnet SDK8 and C#12, I'm getting the following error when upgrading in nuget:-

Package restore failed. Rolling back package changes for 'Web'.
Version conflict detected for Umbraco.Cms.Examine.Lucene. Install/reference Umbraco.Cms.Examine.Lucene 13.1.1 directly to project Web to resolve this issue. 
 Web -> Umbraco.Cms 13.1.1 -> Umbraco.Cms.Targets 13.1.1 -> Umbraco.Cms.StaticAssets 13.1.1 -> Umbraco.Cms.Web.Website 13.1.1 -> Umbraco.Cms.Web.Common 13.1.1 -> Umbraco.Cms.Examine.Lucene (>= 13.1.1 && < 14.0.0) 
 Web -> Our.Umbraco.Extensions.Search 3.1.0 -> Umbraco.Cms.Examine.Lucene (>= 11.0.0 && < 13.0.0).

Similar if I just try to upgrade to V13.1.0 too. Any ideas or tricks? Thanks.

That looks like an issue with Our.Umbraco.Extensions.Search being dependant on Lucene < 13. Someone’s opened a PR to fix it but Callum’s not merged it in yet https://github.com/callumbwhyte/umbraco-search-extensions/pull/11

Thanks. Have given him a nudge on the issue as I'm pretty sure he's not on here and I know he's busy 😉