As part of the native MIME support in R5, the Notes client detects the most appropriate character set for sending a message to the Internet. All the regions listed below are supported.
In addition to the character set support on the client, the R5 Domino Router provides conversion between Notes Rich Text and MIME (for backward compatibility). With respect to international, the Router supports all of the regions listed below. Where previously with the SMTP MTA multiple MTAs were required to provide complete character set support to a WW organization, now only a single R5 Domino Server is required. This extensive character set support is enabled by default when a server has been configured to support SMTP.
The language groups and the associated default character sets are:
| Language Groups | Character Set |
| English | US-ASCII |
| Unicode | UTF-8 |
| Japanese | ISO-2022-JP |
| Simplified Chinese | GB2312 |
| Korea | ISO2022-KR |
| Traditional Chinese | BIG5 |
| Thai | Windows-874 |
| Western | ISO-8859-1 |
| Central European | ISO-8859-2 |
| Baltic Rim | Windows-1257 |
| Cyrillic | KOI8-R |
| Arabic | Windows-1256 |
| Greek | Windows-1253 |
| Hebrew | Windows-1255 |
| Turkish | Windows-1254 |
| Vietnamese | Windows-1258 |