Eskom adjusted their TOU times for high demand season that takes effect 1 June 2015.
The change moves Peak during Winter 1 hour earlier.
Everything else remains the same.
To convert your current Eskom TOU Calendar to the new times
-by the end you will have 1 new day pattern, and 1 new week pattern
-This effects the calendar for Eskom TOU (or Megaflex TOU/Miniflex TOU/Ruraflex TOU); and not Eskom Seasons, Eskom MD, Eskom Peak+STD
1) Currently you should have these day patterns:
-Weekdays
-Saturday
-Sunday
Since it is only Weekdays that are affected, select your Weekdays day pattern, and rename it to Weekdays-Summer
Leave the rate pattern as-is (because the old times and the new summer times are the same)
2) Create a second Day Pattern, called Weekdays-Winter
and change the rate pattern to be the new winter times.
3) Under Week Patterns, rename your Default Week Pattern to Summer.
It should have:
Sun: Sunday
Mon: Weekday Summer
Tue: Weekday Summer
Wed: Weekday Summer
Thu: Weekday Summer
Fri: Weekday Summer
Sat: Saturday
4) Add a new Week Pattern and call it Winter, and set it up like this:
Sun: Sunday
Mon: Weekday Winter
Tue: Weekday Winter
Wed: Weekday Winter
Thu: Weekday Winter
Fri: Weekday Winter
Sat: Saturday
5) Under Year Pattern, for your Season Sequence, leave your Summer Sequence on Week Pattern Summer, and
change your Winter Sequence to Week Pattern Winter.
6) Validate your Calendar.
Remember that this new calendar will not work prior to 2014-09-01.
However this will not affect already run bills (when you run a bill, and publish it, that Monthly Bill will remain the same, regardless of changes made to the tariff afterwards).
If you still need to run bills prior to 2014-09-01, you will need to add a second tariff with its own set of calendars, set up as per the old TOU times, and link that to your Meter Account.

It is now possible to set up your 'season start time' as an absolute date, in other words, not repeating every year. (Do this in the Edit->Year Pattern screen, by clicking on the (HH-MM) link)
What that means, is that as long as you define ALL the seasons for all the years, you can change the week patterns every year, if necessary. It can also accommodate other patterns that are different every year, e.g. the 7 Peak time seasons in Jordan that tracks sunset times, that are potentially different every year.
It can also be used to facilitate a TOU calendar where the times for Winter has now changed, e.g. the new Eskom calendar, to still run Provisional Bills in the past according to the old calendar, and new ones on the new calendar.
However, sometimes it would still be useful to just change the times on the recurring calendar, as per Matiaan's above post. That would for instance enable you to go into the past and see the difference between an old monthly bill, and 'what it would have been if it was on the new calendar' by running a provisional bill for the same historical period. That would enable you without too much reconfiguration to easily allow customers to compare, or do 'dry runs', on existing data, to determine whether the new calendar would constitute a saving or an expense to their business.