How to convert macOS Extended Journaled to APFS? My Macintosh HD is running Sierra from which partition for Mojave was made which doesn’t has APFS option.

Installed Mojave 10.14.2 on a MacBook Pro mid 2012 which has HDD and volume  formatted in macOS Extended Journaled.

Tried to install Xcode 10.2 on Mojave 10.14.2 and got error "this version of Xcode requires Mojave 10.14.3 or later"

Then downloaded macOS Mojave 10.14.4 Combo Update, tried to install it and I got an error:



How to convert the Mojave volume from macOS Extended Journaled to APFS even when convert to APFS option is dimmed in Disk Utility:
This site has instructions on how to convert your drive to APFS. 


Restart the Mac into Recovery Mode.
Launch Disk utility.
Click-select your named boot volume. (Not the physical drive above it.)
In the Disk Utility Edit menu, select “Convert to APFS


More detailed instructions are given in the link above.