The Poco F1 was expected to receive its first taste of MIUI 12 in July but that doesn't appear to be feasible anymore with reports claiming the beta update has now been postponed. The new established timeline will see Poco F1 owners receive the stable update in late August.
https://www.notebookcheck.net/MIUI-12-rollout-for-the-Poco-F1-postponed-stable-update-expected-by-late-August.483587.0.html