Sitecore versions mainstream support, Extended support and Sustaining support
| Product | Initial Release Date | Mainstream Support End Date | Extended Support End Date | Sustaining Support End Date |
| Sitecore 10 | 2020 | 31-Dec-2023 | 31-Dec-2026 | 31-Dec-2028 |
| Sitecore 9.3 | 2019 | 31-Dec-2022 | 31-Dec-2025 | 31-Dec-2027 |
| Sitecore 9.2 | 2019 | 31-Dec-2022 | 31-Dec-2025 | 31-Dec-2027 |
| Sitecore 9.1 | 2018 | 31-Dec-2021 | 31-Dec-2024 | 31-Dec-2026 |
| Sitecore 9.0 | 2017 | 31-Dec-2020 | 31-Dec-2023 | 31-Dec-2025 |
| Sitecore 8.2 | 2016 | 31-Dec-2019 | 31-Dec-2022 | 31-Dec-2024 |
| Sitecore 8.1 | 2015 | 31-Dec-2018 | 31-Dec-2021 | 31-Dec-2023 |
| Sitecore 8.0 | 2015 | 31-Dec-2018 | 31-Dec-2021 | 31-Dec-2023 |
| Sitecore 7.5 | 2014 | 31-Dec-2017 | 31-Dec-2020* | 31-Dec-2022 |
| Sitecore 7.2 | 2014 | 31-Dec-2017 | 31-Dec-2020* | 31-Dec-2022 |
| Sitecore 7.1 | 2013 | 31-Dec-2016 | 31-Dec-2019 | 31-Dec-2021 |
| Sitecore 7.0 | 2013 | 31-Dec-2016 | 31-Dec-2019 | 31-Dec-2021 |
| Sitecore 6.6 | 2012 | 31-Dec-2015 | 31-Dec-2018 | 31-Dec-2020 |
| Sitecore 6.5 | 2011 | 30-Jun-2015 | 31-Dec-2017 | 31-Dec-2020 |
| Sitecore 6.4 | 2010 | 30-Jun-2015 | 31-Dec-2016 | 31-Dec-2020 |
| Sitecore 6.3 | 2010 | 30-Jun-2015 | 31-Dec-2016 | 31-Dec-2020 |
| Sitecore 6.2 | 2009 | 30-Jun-2015 | 31-Dec-2015 | 31-Dec-2020 |
| Sitecore 6.1 | 2009 | 30-Jun-2015 | 31-Dec-2015 | 31-Dec-2020 |
| Sitecore 6.0 | 2008 | 30-Jun-2015 | 30-Jun-2015 | 31-Dec-2016 |
| Sitecore 5.3 | 2006 | - | - | 30-Jun-2015 |
| Sitecore 5.2 | 2006 | - | - | 30-Jun-2015 |
| Sitecore 5.1 | 2005 | - | - | 30-Jun-2015 |
| Sitecore 4.3 | 2004 | - | - | 30-Jun-2015 |
More information on this can be found here - https://kb.sitecore.net/articles/641167