With the release of the Next Generation Schema in May of 2011 we officially deprecated the use of version 1 of our XML API. Now, 6 years later, we feel that we can finally pull the plug on this version of the API — it receives less than 1% of our Web Service traffic.
On the first release after 1 August 2018 we’re going to remove the Web Service version 1 (ws/1 API endpoint) support. If you are one of the few authors of software that has not updated your software to use the newer ws/2 endpoint, your software’s MusicBrainz functionality will cease to work after 1 August.
We think more than 6 years is enough time for people to upgrade their tools. 🙂
MetaBrainz Blog 
Sorry that I did not get the memo until now. I used FOSS tools that did not alert me to the fact the API was changing. So long, and thanks for all the fish.