etc/settings

--- a/etc/settings	Thu Jan 16 15:10:16 2020 +0100
+++ b/etc/settings	Thu Jan 16 15:34:55 2020 +0100
@@ -153,9 +153,9 @@
 
 ISABELLE_STACK_ROOT="$USER_HOME/.stack"
 
-ISABELLE_STACK_RESOLVER="lts-12.26"
+ISABELLE_STACK_RESOLVER="lts-13.19"
 
-ISABELLE_GHC_VERSION="ghc-8.4.4"
+ISABELLE_GHC_VERSION="ghc-8.6.4"
 
 
 ###