Does casting a spell with a longer casting time end a spell that you were previously maintaining concentration on?

Question

From D&D Player's Basic Rules v0.3, p79:

Longer Casting Times

Certain spells (including spells cast as rituals) require more time to cast: minutes or even hours. When you cast a spell with a casting time longer than a single action or reaction, you must spend your action each turn casting the spell, and you must maintain your concentration while you do so (see “Concentration” below). If your concentration is broken, the spell fails, but you don’t expend a spell slot. If you want to try casting the spell again, you must start over.

Does casting a spell with a longer casting time force the caster to end an active Concentration-duration spell?

Answer 1

Yes.

You cannot concentrate on two spells at once, thus casting the second spell, ends the first. Because casting a spell that requires concentration ends the first, and the spell requires concentration for the duration of the casting effort, it's a spell that requires concentration.