Yes,

opkg list | grep cpp
libstdcpp - 5.4.0-1

I have also updated all the packages using

opkg list-upgradable | cut -f 1 -d ' ' | xargs opkg upgrade

but it does not help (Lede is now installed and I also don't know, how to go back to omegaOS)
BusyBox v1.28.3 () built-in shell (ash)

_________ / /\ _ ___ ___ ___

/ LE / \ | | | | | |
/ DE / \ | || || |) | |
// LE \ |||/|| lede-project.org
\ \ DE /
\ LE \ / -----------------------------------------------------------
\ DE \ / Reboot (17.01-SNAPSHOT, r3497-033367e)
_____/ -----------------------------------------------------------

oupgrade --latest

Device Firmware Version: 0.1.10 b160
Checking latest version online...
Repo Firmware Version: 0.2.0 b187
Comparing version numbers
New firmware version available, need to upgrade device firmware
Downloading new firmware ...
/usr/bin/oupgrade: local: line 377: not in a function