ComicBook is quite certain that the first footage from season 4 of Arrow will be unveiled at San Diego Comic-Con in July.

Could Sarab Be Resuscitated In Season 4?  

The official press release stated the details of which DC shows wil be presented:

"8 - 11 p.m. - Warner Bros. Television & DC Entertainment Present: Super Hero Saturday Night Offers Fans a Look Inside the Worlds of Arrow, The Flash and Gotham, plus a Pilot Screening of Supergirl and Video Presentations of DC's Legends of Tomorrow and Vixen: DC fans ... get ready for another Super Hero Saturday Night! Warner Bros. Television and DC Entertainment will again welcome fans into the worlds of some of DC Comics' greatest characters during a three-hour super-experience in Hall H."

Oliver And Felicity's Relationship To Be Challenged In Season 4? 

Recently, Den of Geek speculated that the show will most likely be coming back on Oct. 7. The date is arrived at by studying the premiere dates of the previous three seasons of the CW series, and all of them have been released in the month of October.

The writing for the next chapter has also begun. The creative team put up images on June 1 and 2 of the schedule for the development of episodes. The first said some form of farewell to the white board which featured the schedule for season 3, with each episodes "prep date," "shoot date," and "status/last completed cut." In the next image, the table was being drawn out for season 4.

The announcement of Arrow's renewal for a fourth season was made earlier this month.

The finale of season 3, entitled 'My Name is Oliver Queen,' of Arrow aired on May 13 on The CW.

Watch the promo teaser for season 4: