No, it is not true to say that if something has a constant velocity, it must have constant acceleration. In fact, constant velocity implies zero acceleration.
Acceleration is defined as the rate of change of velocity over time. If an object has constant velocity, it means its speed and direction of motion are constant. In this case, there is no change in velocity, and therefore the acceleration is zero.
When an object has constant velocity, it may be moving at a uniform speed in a straight line or even at rest. In both cases, the object's acceleration is zero because there is no change in its velocity.
It's important to note that in physics, "constant velocity" refers to both constant speed and constant direction. If the direction changes, even if the speed remains constant, there is still acceleration because the velocity is changing.