diff -ur planets-0.1.13.old/options.ml planets-0.1.13/options.ml
--- planets-0.1.13.old/options.ml	2019-04-01 09:06:40.965599836 +0100
+++ planets-0.1.13/options.ml	2019-04-01 09:07:15.128743881 +0100
@@ -16,11 +16,11 @@
   Char.chr ((Char.code 'a') + rand)
 
 let random_name length = 
-  let str = String.create length in
+  let str = Bytes.create length in
   for i = 0 to length -1 do
     str.[i] <-  random_chr ()
   done;
-  str
+  Bytes.to_string str
 
 module StringMap = AugMap.Make(
   struct