On 7 February 2021, 18:01:10 UTC, PrimeGrid’s The Riesel Problem project eliminated k=9221 by finding the mega prime:
The prime is 3,429,397 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 44th overall. This is PrimeGrid's 17th elimination. 47 k's now remain.
The discovery was made by Barry Schnur (BarryAZ) of the United States using an AMD Ryzen 5 2600 Six-Core Processor with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition. This computer took about 2 days, 29 minutes to complete the primality test using LLR2. Barry Schnur is a member of the BOINC Synergy team.
For more details, please see the official announcement.