Magento 2: When will 2.0 support stop?
this has been answered by Ben Marks in an comment on the question Why is Magento 2.1.0 released before 2.0.9?:
Duration of LTS for minor marketing versions (e.g. 2.0, 2.1) is 2 years. – benmarks Aug 30 at 3:15
Update February 27, 2018:
The release notes of Magento 2.0.18 explicitly state: (emphasis mine)
The Magento Open Source 2.0.18 software release marks the final supported software release for Magento Open Source version 2.0.X. Magento Open Source 2.0.X will no longer receive security updates or product quality fixes now that its support window has expired.
Facts & numbers
I have answered this also on this question "Why is Magento 2.1.0 released before 2.0.9?".
Duration of LTS for minor marketing versions (e.g. 2.0, 2.1) is 2 years. – benmarks Aug 30 at 3:15
You could calculate for 2.0 and 2.1 when this support will end based on the 2.0.0 and 2.1.0 announcement and release dates (e.g. on GitHub). For completion I've included the M1 versions (which have 3 years LTS after first M2 release).
| Version | Family | Release date | LTS ending |
+----------+-------------+--------------+------------+
| 2.2.0 | 2.2.x CE&EE | 2017-09-27 | 2019-09-27 |
| 2.1.0 | 2.1.x CE&EE | 2016-06-23 | 2018-06-23 |
| 2.0.0 | 2.0.x CE&EE | 2015-11-17 | 2017-11-17 |
| 1.9.3.0 | CE 1.x.x.x | 2015-10-11 | 2018-11-17 |
| 1.14.3.0 | EE 1.x.x.x | 2016-10-11 | 2018-11-17 |
You see there's a different but clear strategy for M2 support. Where in theory Magento should still support all M1 versions up until November 2018 (and therefor release patches for all 1.x versions, generally they release 1.5 and up). For M2 they have set a LTS on all minor versions.
Enterprise / Commerce
According to the overview in this Enterprise Agreement published on the Magento.com website (thanks Sherrie Rohde for pointing out), there are some dates that deviate from the above. This is explicitly mentioned for Enterprise/Commerce, but nothing is stated about Community/Open Source.
| Release | Release Date | End of Support Date |
+-------------------------+----------------+---------------------+
| Enterprise Edition 1.9 | July 2010 | July 2012 ** |
| Enterprise Edition 1.10 | February 2011 | February 2013 ** |
| Enterprise Edition 1.11 | August 2011 | August 2013 ** |
| Enterprise Edition 1.12 | April 2012 | April 2014 ** |
| Enterprise Edition 1.13 | October 2013 | June 2020 * |
| Enterprise Edition 1.14 | June 2014 | June 2020 * |
| Enterprise Edition 2.0 | November 2015 | March 2018 |
| Enterprise Edition 2.1 | June 2016 | June 2019 |
| Magento Commerce 2.2 | September 2017 | September 2019 |
** Requires a renewal of the Magento license through the stated date.
* Security patches will continue to be provided and made available by Magento through June 2020.
As you can see the end of support for Magento 1 Enterprise has been extended to June 2020. Also the support for Magento 2.0 and 2.1 have been extended by 1 year (3 instead of 2).
I don't have an official source for this but I heard that every 2.X minor version will be supported for 2 years.