I'm developing map-t feature. And an issue of kernel mismatch shows up during map-t package installation.

The dependency of map-t requires kernel  3.18.21-1, but my kernel is 3.18.84-1.

Any method to solve this kernel mismatch? 

This is the error message.
[*]/etc # opkg install map-t
Installing map-t (6) to root...
......
* satisfy_dependencies_for: Cannot satisfy the following dependencies for map-t:
* kernel (= 3.18.21-1-8549f8163c15d79b053f26aa0d52e96f) *
* opkg_install_cmd: Cannot install package map-t.[/*]

My kernel version
[*] /etc # opkg info kernel
Package: kernel
Version: 3.18.84-1-c803b15a552aedd2b1d18f35dcefc111
Depends: libc
Status: install hold installed
Architecture: x86
Installed-Time: 1515737541[/*]