In case you did not see the comments left elsewhere: Albus has said he has a form of experimental magic that may assist those fighting at the camp. He has pressed me into covering his classes, under his likeness; he refused to provide me with any further information.

When he left here, he intended to rendezvous with Frank; I believe it was his intention to have Frank be the one to cast whatever spell he has come up with.

Having been stuck here to tend to the children, I do not, unfortunately, have further information. Hogwarts is quiet; Poppy is keeping an eye on the juniors, and preparing for an evacuation should it become necessary.