Bootstrap3,4,5的变化

img-circle

Bootstrap 3 ✔
Bootstrap 4 替换为rounded-circle
Bootstrap 5 同上

.pull-left和.pull-right

Bootstrap 3 ✔
Bootstrap 4 替换为.float-left和.float-right，同时.float-none的引入是为了去除之前设置的浮动。
Bootstrap 5 替换为.float-start和.float-end

References:
Bootstrap 4 img-circle class doesn't seem to exist

Bootstrap .pull-right and .pull-left not working