I replased tradfri.py3
in /srv/homeassistant/lib/python3.5/site-packages/homeassistant/components with following file:
https://raw.githubusercontent.com/NovapaX/home-assistant/29dca16253f9146cafe8dbca4926a116f3d17a3e/homeassistant/components/tradfri.py
Change log for file: https://github.com/home-assistant/home-assistant/pull/10414
sudo apt-get install build-essential libssl-dev libffi-dev python3-dev autoconf
sudo pip3 install DTLSSocket
git clone https://github.com/ggravlingen/pytradfri.git
cd pytradfri
pip3 install -r requirements.txt
cd ..
git clone –depth 1 –recursive -b dtls https://github.com/home-assistant/libcoap.git
sudo apt-get install libtool
cd libcoap
./autogen.sh
./configure –disable-documentation –disable-shared –without-debug CFLAGS=”-D COAP_DEBUG_FD=stderr”
make
make install
cd pytradfri
python3 setup.py build
sudo python3 setup.py install