diff -r 21ff9c1a4644 -r 979c648ac814 .hgtags
--- a/.hgtags	Sun Nov 29 23:23:32 2020 +0100
+++ b/.hgtags	Mon Nov 30 09:47:05 2020 +0100
@@ -37,3 +37,4 @@
 91162dd89571fb9ddfa36844fdb1a16aea13adcf Isabelle2018
 83774d669b5181fb28d19d7a0219fbf6c6d38aab Isabelle2019
 abf3e80bd815c2c062b02c78b256f7ba27481380 Isabelle2020
+21ff9c1a464494b3a61c3538650664cc1b42c0cb Isabelle2021-RC0