Due to motion warping issues in engine versions 5.3 and 5.4 (experimental state), downgrading isn’t possible. Additionally, assets aren’t compatible with earlier engine versions. For the best experience, I highly recommend upgrading to 5.5 or 5.6! 
Due to motion warping issues in engine versions 5.3 and 5.4 (experimental state), downgrading isn’t possible. Additionally, assets aren’t compatible with earlier engine versions. For the best experience, I highly recommend upgrading to 5.5 or 5.6!