Storing all data in UTC is the correct approach. Make sure that the UTC data is being correctly stored both sides of a DST change at the server location. I've seen many occasions where the UTC data was out by one hour for half the year.
Be aware that many, but not all, users are also subject to DST changes and that these will be on different dates to that experienced by the server, indeed spread over more than a month at each change. Additionally, countries in the Southern hemisphere add the hour six months out of step with the Northern hemisphere.