Before 1995, the UK Summer Time Act stated that in the absence of an overriding Summer Time Order, BST ends at 01:00 GMT on the day after the 4th Saturday in October (which is not always the 4th Sunday in October). The last time the 4th Sunday and Sunday after the 4th Saturday differed was in 1989 when the Act was enforced as normal and 29th October was used. However, for 1995, a Summer Time Order (SI 94/2798) was used to override the Act, and the 22nd October was arbitrarily nominated as the end of BST.
From 1996, the start and end dates for Daylight Savings Time are harmonised across the whole of Europe, as the last Sunday in March and October, respectively.
How this Affects UnixWare
As issued by SCO, all versions of UnixWare 2, and UnixWare 7.0 and 7.1 do not change to and from summer time (Daylight Saving Time) on the correct dates for some or all European Union timezones in the period 1998 to 2001. The autumn change is one month too soon. SCO's web site has instructions on how to correct this in Technical Article and its referenced file TLS710.tar.Z. KE0029499 contains a source file for summer time information for the European Union that is correct for the years 1998 to 2001, that will continue to be correct after 2001 provided that the European Union rules remain unchanged, and which is believed to be correct for the years up to 1997. A script to compile the information is included. The required file is EU2000.tar, attached to KE0029499.
The authoritative source for summer time (daylight saving time) start and end dates for the years 1998 to 2001 in the EU is the Eighth Directive 97/44/EC of the European Parliament and of the Council of 22 July 1997 on summer-time arrangements - Official Journal L 206 , 01/08/1997 (p. 0062 - 0063). The rules for years after 2001 are not yet available - KE0029499 assumes that the rules for 1998 to 2001 will continue in force. It is intended to update this Support Bulletin and the KE during 2001, if the rules are changed from 2002.
ftp://elsie.nci.nih.gov/pub/ Source of much detailed information on timezones.