Clean up based on review.

lib/redis.rb

@@ -9,9 +9,9 @@ class << self
 
     def exists_returns_integer=(value)
       unless value
-        message = "`Redis#exists(key)` will return an Integer in redis-rb 4.3. The option to explicitly disable this " \
-          "behaviour via `Redis.exists_returns_integer` will be removed.  You should use `exists?` instead. " \
-          "(#{::Kernel.caller(1, 1).first})\n"
+        message = "`Redis#exists(key)` will return an Integer by default in redis-rb 4.3. The option to explicitly " \
+          "disable this behaviour via `Redis.exists_returns_integer` will be removed in 5.0.  You should use `exists?` " \
+          "instead. "
 
         ::Kernel.warn(message)
       end
@@ -574,11 +574,11 @@ def unlink(*keys)
   # @return [Integer]
   def exists(*keys)
     if !Redis.exists_returns_integer && keys.size == 1
-      unless Redis.exists_returns_integer == false
-        message = "`Redis#exists(key)` will return an Integer in redis-rb 4.3, if you want to keep the old behavior, " \
-          "use `exists?` instead. To opt-in to the new behavior now you can set Redis.exists_returns_integer = true. " \
-          "To disable this message you can set `Redis.exists_returns_integer = false`, but this option will be " \
-          "removed in the next version. " \
+      if Redis.exists_returns_integer.nil?
+        message = "`Redis#exists(key)` will return an Integer in redis-rb 4.3. `exists?` returns a boolean, you should " \
+          "use it instead. To opt-in to the new behavior now you can set Redis.exists_returns_integer = true. " \
+          "To disable this message and keep the current (boolean) behaviour of 'exists' you can set "
+          "`Redis.exists_returns_integer = false`, but this option will be removed in 5.0. " \
           "(#{::Kernel.caller(1, 1).first})\n"
 
         ::Kernel.warn(message)