Mirza Ghulam Ahmad claimed prophethood through an announcement in Nov-1901.  His team wrote the announcement and got it published.  Amrohi seems to have disagreed at first, however, eventually he agreed to this amendment in the beliefs of MGA.

After 1901, MGA and his team began saying that prophethood was wide open and for all, however, very discreetly.  Later on, in 1907, MGA and his team began to argue that MGA was actually the FINAL Khalifa of the Islamic ummah and only MGA was given the title of prophet. They seem to have lied about hadith in this instance.  They wrote that hadith have prophecied that a person will be born like Esa and will be given the title of prophet, however, this is a lie, there is no such hadith.

The Quote
“”””””From one aspect I am an ‘ummatee’ [follower] and from another aspect, due to the beneficence of the prophethood of His Holiness [Muhammad], blessings of Allaah and peace be upon him, [I] am also a prophet. And the intent of [the term] prophet is only [to connote] that I receive abundant converse and address from God Almighty. The point is that, as Mujaddid Saahib Sarhindee [Sarhindee the Reviver] has written in his books, even though some individuals of this [Muslim] nation have [received or do receive] the special [treatment of] Godly converse and address and will remain special [receiving this treatment] till Resurrection but the person who is honored abundantly with this converse and address and who is abundantly made aware of matters of the unseen, that [person] is called a prophet. Now let it be clear that it
has been prophesied in the Prophet’s hadeeths that, from among the followers of His Holiness [Muhammad], blessings of Allaah and peace be upon him, a person will appear [or be born] who will be referred to as E’esaa [Jesus] and ibn-e-Maryam [son of Mary] and will be known by the name of [i.e., known as] a prophet.

… And this thing is a proven matter that the extent to which God Almighty has made converse and address with me and the extent to which matters of the unseen have been made known to me, no person besides myself has been granted this favor in thirteen hundred Hijree [calendar] years. If some person denies this, the burden of proof is on his neck [i.e., on him].  The point is that in this abundant portion of Godly revelation and unseen matters, from this [Muslim] nation, I am the only special individual and all the ‘auliyaa’ [saints or friends of God] and ‘abdaal’ [saints who move from place to place to hide from public view] and ‘aqtaab’ [religious mendicants, holding a special title of rank] who have gone by before me in this [Muslim] nation – they were not given this abundant portion of this favor/blessing. Hence, for this reason, only I was specially selected for getting the name [i.e., title] of prophet and all the other people are not deserving of this name [i.e., title] because abundance of revelation and abundance of [perception of] unseen matters is a condition of this and that condition is not found in them. And it was necessary that it should have been so, so that the prophecy of His Holiness [Muhammad], blessings of Allaah and peace be upon him, could have been fulfilled with clarity. Because, if other righteous ones who have preceded me, [if] they too, to the same extent, had received a portion of Godly converse and address and unseen matters, they would have become deserving of being known as prophets [and] then in that case a crack [or fault] would have occurred in the prophecy of His Holiness [Muhammad], blessings of Allaah and peace be upon him. That is why the wisdom of God Almighty prevented those respected people from obtaining this favor in a complete manner, just as it appears in authentic hadeeths that such a person will be one only [so that] that prophecy be fulfilled. [RK, v. 22, pp. 406-407; starts at 4th line from top of p. 406, skips some lines below middle of p. 406, then goes on
till about middle of p. 407; Haqeeqat-ul-Wahee; published May 1907]””””
Translated by Nuzhat Haneef in her book vs. Ahmadiyya

Ahmadiyya literature of 1915
In my research work, I had found a quote from the Review of religions from 1915-1916 wherein MGA was called the LAST MESSENGER.  Obviously, Qadiani-Ahmadis saw MGA as the final prophet of Islam.  Ironically, they still argued that prophets could come at any time, depending on the need.  Another form of irony is that the Qadiani-Ahmadis believe that their Khilafat will last til the day of Judgement.  So…in theory, the only prophets in Ahmadiyya would have to be a Khalifa who makes the claim.