In hindsight there was some warning that Sri Lanka might adopt daylight-saving time. In March the Sri Lanka _Sunday Observer_ reported that the government was considering it; see <URL:http://www.lanka.net/lakehouse/anclweb/observr/week5/hotnews/31hot01.html> (1996-03-31). The motivation: Sri Lanka's hydro reservoirs, the source of much of its electrical power, are quite low this year.
This shows the amazing power of the Internet. Who amongst us would have known of the existence of this paper, let alone being able to reach out and read it.
If we don't hear more details about the change, I propose that we assume that Sri Lanka changed clocks at 1996-07-21 02:00 and that they'll continue to use daylight-saving time until further notice (I'll include this in a proposed patch that I'm preparing).
I didn't check with a calendar when I just counted back ten days from the Times issue date to guess at 21 July. Note that the Sunday Observer story says it would have to be done on a Saturday at 2 am. Maybe they consider 2 am Sunday morning to be still part of Saturday night, but maybe they do mean 2 am on Saturday. Peter Ilieve peter@aldie.co.uk