| Access Modifiers in C# | ||||||
| Modifiers | 2003 | 2005 | 2008 | 2010 | 2012 | 2013 |
| abstract | yes | yes | yes | yes | yes | yes |
| async | – | – | – | – | yes | yes |
| const | yes | yes | yes | yes | yes | yes |
| event | yes | yes | yes | yes | yes | yes |
| extern | yes | yes | yes | yes | yes | yes |
| in | – | – | – | yes | yes | yes |
| out | – | – | – | yes | yes | yes |
| override | yes | yes | yes | yes | yes | yes |
| readonly | yes | yes | yes | yes | yes | yes |
| sealed | yes | yes | yes | yes | yes | yes |
| static | yes | yes | yes | yes | yes | yes |
| unsafe | yes | yes | yes | yes | yes | yes |
| virtual | yes | yes | yes | yes | yes | yes |
| volatile | yes | yes | yes | yes | yes | yes |