The Diary of River Song: Series 3.

Good news for fans of River Song. Big Finish Studios has announced that a third series of the "Diary of River Song" will be released in January of 2018.
The sexy time travelling archeaologist and wife of the Doctor will be back for 4 more thrilling adventures starring Alex Kingston, reprising her role first seen in the 2008's "Silence in the Library." Peter Davison is set to appear again as the Fifth Doctor. Frances Barber will also be appearing as the sinister Madame Kovarian (last seen in 2012's "The Wedding of River Song.)
Big Finish has released these synopses for the 4 stories:

"3.1 – The Lady in the Lake by Nev Fountain
On Terminus Prime, clients choose their own means of demise. Something exciting, meaningful, or heroic to end it all.
But when River discovers that there are repeat customers, she knowsGood news for fans of River Song. Big Finish Studios has announced that a third series of the "Diary of River Song" will be released in January of 2018.
The sexy time travelling archeaologist and wife of the Doctor will be back for 4 more thrilling adventures starring Alex Kingston, reprising her role first seen in the 2008's "Silence in the Library." Peter Davison is set to appear again as the Fifth Doctor. Frances Barber will also be appearing as the sinister Madame Kovarian (last seen in 2012's "The Wedding of River Song.)
Big Finish has released these synopses for the 4 stories:

"3.1 – The Lady in the Lake by Nev Fountain
On Terminus Prime, clients choose their own means of demise. Something exciting, meaningful, or heroic to end it all.
But when River discovers that there are repeat customers, she knows something more is going on.
She begins to uncover a cult with worrying abilities. Its members can apparently cheat death, and that’s not all they have in common with River…
3.2 – A Requiem for the Doctor by Jac Rayner
River has joined the Doctor and his friend Brooke on their travels, and they stop off in 18th century Vienna.
Brooke thinks history is dull. Until people start dying.
Mozart’s legacy is not just his music. River has more than one mystery to solve before a killer is let loose on the people of Vienna – and on the Doctor.
3.3 – My Dinner with Andrew by John Dorney
Welcome, Mesdames et Messieurs, to The Bumptious Gastropod.
The most exclusive, most discreet dining experience outside the universe. For the restaurant exists beyond spacetime itself, and the usual rules of causality do not apply. Anything could happen.
It is here that the Doctor has a date. With River Song. And with death.
3.4 – The Furies by Matt Fitton
Stories of the Furies abound across the cosmos: vengeful spirits hounding guilty souls to death. Madame Kovarian taught them to a child raised in fear, trained to kill, and placed inside a spacesuit.
Kovarian knows the universe’s greatest threat, the Doctor must be eliminated. An assassin was created for that purpose.
But if Melody Pond has failed, Kovarian will simply have to try again."

According to the Big Finish website, a fourth series will be released in January of 2018 as well, starring Alex Kingston again, as well as Tom Baker as the Fourth Doctor. A fifth series is expected out in January of 2019.
River Song's future on "Doctor Who" is still up in the air. Her story was effectively wrapped up in the 2015 Christmas Special, "The Husbands of River Song," but in the realm of science fiction anything is possible.