They estimate 20.00 to midnight on Monday night, but expect a shorter window.
Posted on 26 June 2015 - AnnouncementWe're now planning for this, so we'll be in touch with you as to what we advise to minimize impact to your servers and applications hosted in that facility.
They estimate a start time of 8pm, with a maximum interruption of 4 hours (probably much less).
The decision to move the window back 24hrs seems sensible to us in the circumstances, and for the little its worth, we fully support that in terms of risk management.
Any initial questions, please contact us via the normal means.