@xme I've just downloaded and installed libidn2-0_2.0.5-1_armhf.deb and libidn2-dev_2.0.5-1_armhf.deb.
Hope, it'll help, if you choose packages for your architecture.
In case that the Codeception 3.0 does fail with fatal errors, head up to this blog post https://t.co/ucc8DqirZI przez @codeception#testing#unit#development