Pix-Art Messenger will remove the implementation of OTR encryption by 30th June of 2020.
Unfortunately, it does not make sense to continue support on a rather out-dated technology, even as we see some users keep using it. For the moment, OTR (as well as OpenPGP) can be activated via the expert settings for advanced users. Pix-Art Messenger always tries to be usable for even [non-technical users](https://github.com/kriztan/Pix-Art-Messenger/issues/227), OTR however is not counted as appropriate for this.
Please consider to use OMEMO in the future, many other clients has implemented this, have a look at [omemo.top](https://omemo.top/). However, if you really need to continue using it, please refer to e.g. [Miranda](https://www.miranda-ng.org/de/), [Pidgin plugin](https://github.com/gkdr/lurch/), [Profanity](https://profanity-im.github.io/) or [Coy.im](https://coy.im/). You are also able to fork Pix-Art Messenger and continue the implementation on your own.