"you have to still try to do better if you want to keep it that way ;)" roughly means: Nothing is ever perfect but we should actively seek continuous improvement, as well as try hard to identify weaknesses in order to correct them. After 3 years here, I am slowly learning. Wie Rewe, jeden tag ein bisschen besser.

edit: this is why it is typically un-German to boost, and more typically German to complain -- they are just pointing out what to fix!