To install BokaIRC.apk is completely secure. The warning you receiving is because BokaIRC.apk is not on Google PlayStore yet. Follow the picture tutorials to install our BokaIRC Application to your device.
The above picture shows you how to click the more option circled by a green marker.
Please click "Install without Scanning" to install our app to your devices. Again, this is highly secure. The Google security warning you are seeing is because the BokaIRC Application is not on the Google PlayStore.