June 19th is the Monday after Trooping the Colour, which is always the day reserved for Garter Day. The Queen has therefore decided to cancel this year's service for the Order of the Garter.
The State Opening coming so soon after Trooping the Colour does not leave enough time for practice of the ceremony, according to today's announcements, and so the 2017 State Opening will be a "dressed down" version. There will be no carriage procession to Parliament, and The Prince of Wales and The Duchess of Cornwall will not be present. The Imperial State Crown will be present, but it will not be worn by The Queen; she'll be expected in her usual daywear instead of a gown.
March 1974 -- the last time a "dressed down" Queen attended the State Opening of Parliament pic.twitter.com/Mbh0LQUC4z— Peter Hunt (@BBCPeterHunt) April 27, 2017
The last time the State Opening of Parliament took place in this "dressed down" format was in March 1974. The BBC's Peter Hunt shared the above video of The Queen's arrival for the event, giving you an idea of what expect in 2017. The Queen wore her usual day outfit with hat; it looks to be her outfit from Princess Anne's first wedding. In 1974 there were actually two State Openings of Parliament, because there were two elections. The full crown-n'-gown procedure was in place for the October ceremony.
This Times Court Circular describes the scaled down ceremony for March 1974 State Opening. On this ocassion, HM came alone by car. pic.twitter.com/rxjL5pSt7F— Matthew Purvis (@HLLibResearch) April 27, 2017
Officials are insisting that this is not a permanent change - things will go back to the usual pomp and circumstance in 2018 - and that it is not due to any concerns regarding The Queen's age. A slight change was made in 2016, when The Queen took the elevator instead of the stairs during the State Opening.
Of course, the election has also had another effect on the royal schedule: the Spanish state visit has been pushed back to July 12-14. (Better than an indefinite delay, at least!)