diff --git a/lib/iruby/kernel.rb b/lib/iruby/kernel.rb
index ffe581c..a2cd652 100644
--- a/lib/iruby/kernel.rb
+++ b/lib/iruby/kernel.rb
@@ -218,7 +218,8 @@ def execute_request(msg)
       end
 
       events.trigger(:post_execute)
-      events.trigger(:post_run_cell, result) unless silent
+      # **{} is for Ruby2.7. Gnuplot#to_hash returns an Array.
+      events.trigger(:post_run_cell, result, **{}) unless silent
 
       @session.send(:reply, :execute_reply, content)
     end