(oops, sent it directly instead of to the list at first) On Sun, Sep 2, 2012, at 00:12, lord.buddha@gmail.com wrote:
I now also wonder if the presumption of a pattern might cause conflicts with other sources. IATA / Microsoft etc.
I think Microsoft's practice has generally been to have extrapolated rules, hope for the best, and publish a hotfix if it doesn't match. My (unpatched) Windows 7 machine extends the 2010 rule [Fourth Sunday October to Last Sunday March] on to infinity. They have published at least two updates since then that I've been able to find that tweak the rules, and I haven't verified firsthand but have no particular reason to doubt they similarly extend the then-latest rules [Fourth Sunday January to First Sunday March, based on update description text] indefinitely, and expect to publish further hotfixes. -- Random832