Kesubos, Chapter 4, Mishnah 12. This mishnah deals with one more condition of the kesubah - the last of these conditions - which remains in force even if it was not written into the document. This condition concerns what happens after the husband's death: the widow's right to continue living in his home and to be supported from his estate.
The words of the mishnah:
"At tehei yasva b'veisi" - you, my wife, shall live in my home after my death.
"Mitazna minichsai" - and you shall be supported from my estate.
"Kol yemei migad almenuseich b'veisi" - for the entire time that you remain a widow in my home, until you marry another man.
"Chayav" - even if the husband did not write this condition, the estate is obligated in it, since this is a condition instituted by the court.
Two versions of how the condition was written:
The people of Jerusalem and the Galilee: "This is how the people of Jerusalem would write," and likewise "the people of the Galilee would write as the people of Jerusalem did" - in the wording quoted above.
The people of Judea: The people of Judea outside of Jerusalem would write a slightly different version, with a different meaning: you may live in my home and be supported from my property - "ad sheyirtzu hayorshim liten lach kesubaseich" - until the heirs wish to give you your kesubah.
According to the version of the people of Judea, "if the heirs wished" to give her the kesubah, they may give it to her and thereby be released from the obligation to support her. It is in their hands to end the arrangement by paying the kesubah.
In summary: This is the difference between the two versions of the kesubah condition. According to the version of the people of Jerusalem and the Galilee, the matter does not depend on the heirs but on her, and she is the one who can end the arrangement; whereas according to the version of the people of Judea, the heirs have the power to end the arrangement by paying the kesubah.