I tried latest hello.rs from blue-pill . However got build error "error: language item required, but not found: panic_fmt". Fixed the app by adding panic handler related code as per "cortex-m-quickstart" examples/panic.rs. However earlier version of cortex-m-rtfm didn't require such modification. Looked into the code of cortext-m-rtfm. I found that panic handler was part of cortex-m-rtfm earlier version. However there is no panic handler in the latest cortex-m-rtfm.

So am my missing any thing? or should panic handler be part of latest cortex-m-rtfm?