There's no date on this letter.

这封信未注明日期。

《牛津词典》

Even so, this is where your reader is going to look to find your address and the date the letter was written, so it should be there.

尽管这样，当读信人想知道信来自何方，以及写于何时，他们仍会到这里去查找。所以现在也仍要这样写。

youdao

Your letter of the.. crossed ours of the same date.

贵方…月…日函刚好错过我方同日信函。

youdao

Now,notice that means that some people would say that they use that 367 date,when Bishop Athanasius sent around his Easter letter. And they say that's when the Christian canon of the New Testament was set.

有些人会说,它写于主后367年，即阿萨内修斯主教,分发复活节书信的时候,据说那就是确定基督教新约正典的时间。

耶鲁公开课 - 新约课程节选

The university asked me to provide an up-to-date sponsor letter, which I couldn't get hold of because of the situation in Syria.

BBC: Syrian students face fees crisis

"I have visited the factory a couple of times, " the letter date Feb. 8 reads, according to a copy published Wednesday in Les Echos newspaper.

NPR: US CEO Ridicules French Workers As Time-Wasting

Although the Notice of Claim Disallowance letter sent by the Service generally contains a statement advising the taxpayer that the two-year period began on the date of the letter, the Service occasionally mails these letters without the paragraph notifying the taxpayer of the two-year period for filing suit.

FORBES: When It Comes to the Two Year Statute - You are on Your Own