Where did you get this idea, not to mention the confidence to repeat it authoritatively? It's the opposite of correct: not only is this NOT true (GMT does NOT have daylight savings time or spring forward/fall back at any point during the year) but there are other differences between GMT and UTC as well.

The difference is in fraction of seconds, from the parent link:

> The term GMT is now more commonly used to refer to the time zone at the prime meridian (0° longitude), in which case it is being used as a local representation of Coordinated Universal Time (UTC) and not UT1. However, UTC is adjusted with leap seconds to always be within less than one second of UT1, so either use of GMT can be considered equivalent to Coordinated Universal Time (UTC) when fractions of a second are not important.

No - that’s incorrect. From a civil time perspective, the UK keeps to GMT during the winter but BST during the summer.

The difference (such as it is) is that GMT is a time zone and UTC is technically not: it is a time standard.

It's clear I didn't communicate this properly but that was my point – UTC is not a time zone like GMT.

And I don't know the name of British DST (I used the american name), so yeah, bad wording but this was essentially what I was trying to communicate.

Never use software that thinks in terms of lists of +/- GMT zones and says things like "GMT: Ireland, United Kingdom; Iceland". You don't live in a "GMT Time Zone" and nobody you know has any idea what this means.

Use software which is driven by cities and uses the Olson database, Europe/London, Europe/Dublin and so on. This is unambiguous which means things will go wrong a lot less often.

You probably live in a city, and if you don't live in a city you there's a big one near you. You know what time it is there. Everybody knows what time it is there. If you're participating in an event where some people are far away they can do any number of things to find out when "14:00 Dublin time" is exactly and get it correct. They can even just call somebody in Dublin and ask. No confusion about "Um, GMT. I think? Is the timezone GMT? Or UTC? Or does it change?"

If by "use software" you mean "pick a time library for your product", then I think I agree.

If you mean "use software" then this seems a little extreme.

This is what I do – I store account time zones in my DB using "America/New_York" etc, rather than an hour offset.