Not really sure where to post this but

I noticed recently that the BusyBox v1.25.1 (2017-12-12 01:53:15 CET) multi-call binary implementation of find does not include the -newer option…

In DD-WRT, which has BusyBox v1.27.0 (2017-07-19 05:18:28 CEST) built-in shell (ash), -newer is supported

Al

Well turris can’t kind of keep up pace with speed of development in order not to sacrifice stability. But to your problem you can always get source code of find command here http://ftp.gnu.org/pub/gnu/findutils/ as described here https://www.gnu.org/software/findutils/ and try to compile it into binary yourself with toolchain or under lxc and then use final result binary fille by calling it from fully qualified path to make sure compiled binary find version is called instead of busybox.