Fix iOS 11.3.1 Cydia dpkg_locked error

To Fix iOS 11.3.1 Cydia dpkg_locked error, You don’t need to restart/re-jailbreak.

Use the following commands to fix the error of dkpg_locked.

We will move dkpg folder from /Library to /Private/var/lib/ to fix the dkpg_locked error in Cydia on jailborken iOS 11.3.1

cd /Private/var/
mkdir lib
mv /Library/dkpg /Private/var/lib/

Then simply reload Cydia and it should now ask you to upgrade essential or complete and you’re done.