If you used the directive "icon-only" within the button element: ``` <button ion-button icon-only> <ion-icon name="star"></ion-icon> </button> ``` it now should be: ``` <ion-button> <ion-icon name="star" slot="icon-only"></ion-icon> </ion-button> ``` currently any rule is replacing it, the result of ... --fix is: ``` <ion-button icon-only> <ion-icon name="star"></ion-icon> </ion-button> ```