system: You are a contract-analysis assistant performing a span-extraction task. You are given an excerpt from a commercial contract and the name of a clause type to locate within it.

Return the exact text of the requested clause, copied verbatim from the excerpt — identical wording and punctuation, with no paraphrasing, summarising, explanation, or added commentary.

The excerpt is one window of a much longer contract and often will not contain the requested clause. If the requested clause does not appear in this excerpt, respond with exactly: Not found.

Output only the extracted clause text, or the exact string `Not found.` — nothing else.

user: Contract excerpt:
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is first used by or on behalf of ELEPHANT TALK to provide the ELEPHANT TALK Wholesale Services under this Agreement. 16. SIM CARDS & CALLING CREDIT Source: PARETEUM CORP, 8-K, 10/1/2008 CONFIDENTIAL TREATMENT REQUESTED WITH RESPECT TO CERTAIN PORTIONS HEREOF DENOTED WITH "***" Hosting Agreement between ELEPHANT TALK and T-Mobile, 18/9/2008 16.1 ELEPHANT TALK shall order and purchase SIM cards. 16.2 In principle the *** will be of *** will remain the property of T-Mobile at all times. 16.3 T-Mobile shall retain at all times full ownership of its intellectual property rights vested in the software (including T-Moible's and its supplier related software and codes, but excluding typical ELEPHANT TALK's and/or other party's content) contained in the T-Mobile IMSI's. 16.4 Parties agree that they will re-discuss the provisioning of a ***, the implementation and associated costs of the *** shall be considered part of the Agreement and therefore shall not result in additional costs for ELEPHANT TALK provided that no *** are involved. ELEPHANT TALK shall retain at all times full ownership of its intellectual property rights vested in the software contained in the ***. . 16.5 T-Mobile has a strict policy with respect to the usage of *** (also known as "*** ") and any other devices that ***"). These *** are under no circumstances allowed on the T-Mobile Network. ELEPHANT TALK is aware of T-Mobile's position with respect to these *** and will refrain from using *** or from doing business with any party (including ELEPHANT TALK's Customers), who uses these *** to the T-Mobile Network. Furthermore, duplicating the *** or functionalities of the *** without the explicit prior written approval of T- Mobile is forbidden. ELEPHANT TALK will (contractually) inform the ELEPHANT TALK Customers that they will refrain from using *** or ***. T-Mobile herewith gives ELEPHANT TALK approval to *** once, only for the purpose of supplying *** as commonly known in the market at the moment of signing the Agreement, to ELEPHANT TALK Customers, only to be used by end users of ELEPHANT TALK Customers for normal end user purposes. Parties shall use their reasonable endeavors to co-operate in order to prevent and clarify any misuse of *** or use of ***. In the event that T-Mobile discovers such improper use or forbidden acts of ELEPHANT TALK Customers, Parties shall contact each other's fraud manager immediately, in order to stipulate details and take appropriate measures. In addition, ELEPHANT TALK shall do its best to stop these actions immediately on first request of T-Mobile. Should ELEPHANT TALK wilfully or negligently fail to comply with an T-Mobile request, ELEPHANT TALK shall bear full responsibility and indemnify T- Mobile for all damages and losses T-Mobile suffers resulting from actions as mentioned in this article by ELEPHANT TALK's Customers. 17. DURATION OF THE AGREEMENT 17.1 This Agreement shall come into force on the Date of the Agreement, and shall, subject to article 18, remain in full force and effect for an initial period of *** from the Commercial Launch Date. 17.2 The Agreement may be terminated by both Parties with a notification period of *** before the end of the Initial Term of the Agreement. If no termination notice is provided, the Agreement will be automatically extended for consecutive *** periods until such time as *** termination notice is provided. At the end of *** Parties will negotiate in good faith regarding a possible extension of the Initial Term. Parties can mutually agree in writing to deviate from an automatic extension of *** by extending this Agreement for a longer period than ***. Source: PARETEUM CORP, 8-K, 10/1/2008 CONFIDENTIAL TREATMENT REQUESTED WITH RESPECT TO CERTAIN PORTIONS HEREOF DENOTED WITH "***" Hosting Agreement between ELEPHANT TALK and T-Mobile, 18/9/2008 18. TERMINATION OF AGREEMENT 18.1 In addition to the conditions of Article 17, this Agreement may be terminated as follows: a. by mutual agreement of the Parties; or b. by either Party, with immediate effect, if the other Party is in material breach of any provision of this Agreement and does not or is not capable of remedying such breach within a reasonable time and in any event within sixty (60) Business Days of receipt of a written notice to such effect. A material breach will, for the purpose of this Agreement, not include the event that ELEPHANT TALK fails to comply with its payments obligations under article 9.2.; or c. by T-Mobile, if ELEPHANT TALK fails to comply with its obligations under article 16.5 upon written notification thereof by T-Mobile,
"""

Extract the exact clause related to "Expiration Date" from the excerpt above.

assistant: This Agreement shall come into force on the Date of the Agreement, and shall, subject to article 18, remain in full force and effect for an initial period of *** from the Commercial Launch Date.