I just upgraded this site to WordPress 2.5 and Tiga v2.3 appears to be working just fine.
If you are running Tiga v2.3 already should be able to upgrade  to WordPress v2.5 with no major problems.
If you are running an older version of the Tiga theme, install the 2.2/2.3 patch , then upgrade to WordPress v2.5.
If there are any general  problems with the Tiga v2.3 theme under WordPress 2.5, you can leave a response under this thread.
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