A company plans to migrate a custom task tracking solution to SharePoint Online. The solution includes customized master pages, timer jobs, and content by query web parts. You need to migrate the…

Setting content by query web parts to unthrottled requests does not resolve their incompatibility with SharePoint Online or address the unsupported timer jobs and master pages.

Replacing content by query web parts with content search web parts changes only the web part type and does not resolve the migration blockers of custom master pages and timer jobs in SharePoint Online.

SharePoint Online does not allow full-trust farm solutions, so a sandboxed solution is the supported model for hosting custom code in the cloud environment. Sandboxed solutions run in an isolated, resource-restricted environment that SharePoint Online permits, providing a viable path to migrate existing customizations. This approach maintains long-term supportability within SharePoint Online's allowed customization boundaries.

Rewriting as an app (SharePoint Add-in) is a valid modernization path but requires more extensive redesign and does not natively replicate timer job or master page behavior, making it harder to maintain feature parity.