Do i need to make asset bundles with upgraded Unity version?

Hi All, I am facing a difficult situation, need guidance in this. I have around 100 asset bundles uploaded which i am using in my app. I upgraded Unity to 2018.3. Now when i download asset bundle it turns black. Now, my question is should i Upload again all my asset bundles again? with unity 2018.3? Isn't this a bug time consuming task and on every update i should do all this again and again.