Update.

bibs/header.bib

@@ -180,6 +180,8 @@
 @STRING{popl18      = popl # ", Los Angeles, California" }
 @STRING{popl19      = popl # ", Lisbon, Portugal" }
 @STRING{popl20      = popl # ", New Orleans, Louisiana" }
+@STRING{popl21      = popl }
+
 % ----
 @STRING{icfp        = "{ACM} {SIGPLAN} {I}nternational {C}onference on
                       {F}unctional {P}rogramming ({ICFP})" }
@@ -218,6 +220,8 @@
 @STRING{ccs16       = ccs # ", Vienna, Austria" }
 @STRING{ccs17       = ccs # ", Dallas, Texas" }
 @STRING{ccs18       = ccs # ", Toronto, Ontario" }
+@STRING{ccs19       = ccs # ", London, England" }
+@STRING{ccs20       = ccs }
 
 @STRING{dbpl        = {Database Programming Languages (DBPL)}}
 @STRING{dbpl05      = dbpl}
@@ -240,6 +244,7 @@
 @STRING{oopsla14    = oopsla # ", Portland, Oregon" }
 % ----
 @STRING{lics        = "{IEEE} {S}ymposium on {L}ogic in {C}omputer {S}cience ({LICS})" }
+@STRING{licspost20  = "{ACM/IEEE} {S}ymposium on {L}ogic in {C}omputer {S}cience ({LICS})" }
 @STRING{lics86      = lics # ", Cambridge, Massachusetts" }
 @STRING{lics87      = lics # ", Ithaca, New York" }
 @STRING{lics88      = lics # ", Edinburgh, Scotland" }
@@ -264,6 +269,7 @@
 @STRING{lics16      = lics # ", New York, New York" }
 @STRING{lics17      = lics # ", Reykjavik, Iceland" }
 @STRING{lics19      = lics # ", Vancouver, British Columbia" }
+@STRING{lics20      = licspost20 # ", Saarbr{\"{u}}cken, Germany" }
 % ----
 @STRING{pldi        = "{ACM SIGPLAN Conference on Programming Language Design
                       and Implementation (PLDI)}" }