Token ex added extra tokens, your tokens, to the Drupal token system. Token ex is decommissioned in favour of Custom Tokens, a slightly different module doing most of what Token ex did.
You can get Custom Tokens from drupal.org/project/token_custom. The module is currently at beta 2 and works in the sites where I tested it. Although it is not an exact replacement for token ex, it achieves the same purpose.
The new version 2 of Custom Tokens lets you prevent the use of PHP in tokens through filters, something done in Token ex with permissions. Permissions are easier for many things. Filters have the same effect for the most common uses of Token ex. After the little bit of thinking required to set up Custom Tokens, the difference will not add work.
Time to focus on other modules
Replacing Token ex with Custom Tokens will give me time to focus on other modules in use at more sites than Token ex.