You have me confused !!! So I went and searched for an end of life announcement and could not find it....
The RedbearDuo is out of stock at Particle. That is because Particle is at full capacity shipping out the new ParticleMesh product line. The announcement on the Particle store indicates that RedbearDuo should be back in stock by the end of October. Mesh was a little bit late, so it would not surprise me that the Duo is also late. I am a bit disappointed that the re-stocking is late.
However, various Particle distributors still have stock. I am still finding them available somewhat locally to where I am.
The latest news on the RedbearDuo from the Particle General Manager is here: