According to the Kent County Council website:

The Kent History and Library Centre, James Whatman Way, will open Monday 23 April at 9.00am. The centre will be home for Kent’s unique and rich archive collection and include a brand new library.
As part of the ongoing preparations for the move, Maidstone Library - which currently offers access to some of the microform records - will close on Monday 26 March.
For more information telephone 08458 247200.

Cannot wait to see what it looks like! If you need to see parish registers for Canterbury churches the Canterbury Cathedral Archive is now closed until the autumn for refurb but some microfilms are available at other places one of which was Maidstone Library! Best to check where they are before travelling.