The PowerShot G1 X Mark III is scheduled to be announced in mid October. There has been some speculation that we might see the PowerShot G3 X Mark II announced as well, which we now know isn't happening in 2017.
It appears is the PowerShot G1 X Mark III will be the last substantial camera announcement from Canon for the remainder of the year. We expect to see more PowerShot G series cameras announced ahead of CES 2018 which begins on January 9, 2018.
DSLR announcements generally come in February ahead of CP+.
Here's hoping the PowerShot G1 X Mark III is a big step forward for the “G” series.