Update isc-2025.md

Author: OliveCannon

content/en/events/isc-2025.md

@@ -40,7 +40,7 @@ This special 24-hour global event celebrates our 10th anniversary with sessions
 
 Each presentation will be delivered live, lasting approximately 20 minutes, followed by a brief discussion. Speakers should plan to present live and, if possible, in person at one of our event locations.
 
-Proposal submissions are due by **5PM GMT on Monday, July 15th**.
+Proposal submissions are due by **5PM GMT on Sunday, August 31st**.
 
 InnerSource Commons presentations will be any topic that is related to the practice of InnerSource. Here are a few topic ideas, others are welcome:
 
@@ -62,7 +62,7 @@ To submit a CFP, please visit [InnerSource Summit 2025 - Call for Presenters](ht
 
 ## Talk Submission Timelines
 Monday, May 12 – 2025 CFP Opens <br />
-Monday, July 15th at 5PM GMT – 2025 CFP Closes <br />
+Friday, August 31st at 5PM GMT – 2025 CFP Closes <br />
 September – Communication from the InnerSource Commons Summit team on status updates and final speaker schedule announcement <br />
 <br />