The witnesses (“whereof”) that many drafters refer to in the signature block? They are a ludricous inheritance of Medieval Common Law culture. Get rid of them in agreements (but you would need them in English law governed ‘deeds’).
The final part of a contract shows some cultural differences in presentation between US style and European style contracts:
Yes! In modern contracts, the signature blocks are introduced by a so-called concluding clause:
THUS, this Agreement was executed on the date first above written.
Not! Its old-fashioned counterpart in common law context is different:
IN WITNESS WHEREOF, the parties hereto, intending to be legally bound, have caused their proper and duly authorized officers to execute and deliver these presents as of the day and year first above written.
First, an assertion that the parties have caused the agreement to be executed by their duly authorized officers, as may also be found, does not serve any purpose. A legal entity by its very nature can only enter into the agreement through representation by one or more natural persons. Second, you should not include a warranty in the concluding clause expressing that the executing natural person is authorised. If the signatory is not authorized to bind the party that he or she alleges to represent (and that party does not ratify such lack of authority), the law of mandate or agency will impose liability on the unauthorized signatory for the full extent of the other party’s damages. Third, the phrase intending to be legally bound is nonsense: it is not a prerequisite to the enforceability of a contract that the parties explicitly express such intention. Fourth, the sentence contains a number of archaisms: IN WITNESS WHEREOF should, like WITNESSETH before the preamble, be dispensed with not only because contracts rarely need to be witnessed but also because it is old-fashioned. Finally, these presents is an outdated alternative for this agreement.
The phrase the day and year first above written is woolly. It is appropriate to refer to the signing date (or effective date) but make sure such date appears only once on the document if you do include something like on the date first above written). If you want each signatory to note the signing date, place underneath each signature line the notation Date:.
Bottom line. Altogether, you can dispense with the concluding clause, insofar as it extends beyond one single (visually separating) line of text. Anything it says, essentially states the obvious. The message should visually convey the same logical and natural transition as the parties block, the preamble title and the words of agreement. However, in the Weagree Wizard you can replace either version of a concluding sentence by the same one click of the aforementioned button.
 See for example the Draft Common Frame of Reference (Art. II 6:107) on representation.