The fourth challenge of the 2021 Series will be a 5-day challenge celebrating the 16th anniversary of the launch of PrimeGrid on BOINC. The challenge will be offered on the ESP-LLR application, beginning 12 June 13:00 UTC and ending 17 June 13:00 UTC.
To participate in the Challenge, please select only the Extended Sierpinski Problem LLR (ESP) project in your PrimeGrid preferences section.
For more information, check out the forum thread for this challenge:
Best of luck!