A treaty does not enter into force when it is adopted.
Typically, the provisions of the treaty determine the date on which the treaty enters into force, often at a specified time following its ratification or accession by a fixed number of States.
For example, the Convention on the Rights of the Child entered into force on 2 September 1990—the 30th day following the deposit of the 20th State’s instrument of ratification or accession. A treaty enters into force only for those states which gave the required consent.
Entry into force in the EUCLID context
Both 49006 and 49007 entered into force upon second signature, which is the default mechanism:
Open Memorandum of Understanding (MOU) between the Participating EUCLID Parties regarding their Participation in the Educational Framework defined
herein (with annex). New York, 5 March 2008
Entry into force: 16 April 2008, in accordance with articles III and VI
Updated Framework Agreement regarding the Parties’ Participation in EUCLID as Constituted and Defined herein. New York, 28 July 2009
Entry into force: 3 September 2009, in accordance with article VI
On Wikipedia (not professional but useful in this case: Treaties that have not yet entered into force