diff --git a/new-version.rb b/new-version.rb
new file mode 100644
index 0000000..c25e486
--- /dev/null
+++ b/new-version.rb
@@ -0,0 +1,34 @@
+engine, version = ARGV.fetch(0).split('-', 2)
+
+MATCH = case engine
+when 'ruby', 'jruby'
+  /^\d+\.\d+\./
+when 'truffleruby'
+  /^\d+\./
+end
+
+raise unless version[MATCH]
+
+file = "#{__dir__}/ruby-builder-versions.json"
+lines = File.readlines(file, chomp: true)
+
+from = lines.index { |line| line =~ /"#{engine}": \[/ }
+to = from
+to += 1 until lines[to].include?(']')
+
+from += 1 # [
+to -= 2 # head, ]
+
+puts lines[from..to]
+
+release_line = lines[from..to].find { |line|
+  v = line[/"([^"]+)"/, 1] and v[MATCH] == version[MATCH]
+}
+
+if release_line
+  release_line << " #{version.inspect},"
+else
+  lines.insert to+1, "    #{version.inspect},"
+end
+
+File.write(file, lines.join("\n") + "\n")