In such a case, it is common for my country to describe Subscription End Date 2017/12/31. Of course, essentially it means 2017/12/31 23:59:59.999.... (That is, it does not mean "the subscriptions ends at midnight (00:00:00 hours) on 2017/12/31".)
I understand now. There are two ways of expressing Subscription End Date:
The Subscription expires at the moment the date stated in Subscription End Date begins (That is, in the case of written as 2018/01/01)
The Subscription expires at the moment the date ended in Subscription End Date begins (That is, in the case of written as 2017/12/31)
Both have the same meaning.
I only know about Japan. So I think that denoting Subscription End Date as "2017/12/31" may be minor and may not global standard. I want to ask everyone. How do you describe Subscription End Date in your country?
* Note: I am aware of the following:
The same as above applies to Subscription.TermEndDate.
The same as above applies to RatePlanCharge.EffectiveEndDate
Great question, but basically the answer is that this is how Zuora works. The Subscription/Term/Effective end date is actually the day AFTER the expected end date, or to put a more positive presentation on this, it's the FIRST day of the renewal!
Zuora has always done this. I'd also ask you to remember that a day is the smallest unit of measure of time in Zuora for subscription events. A subscription can't begin at 11am PST on January 15th, it can only begin (or end) on January 15th. With WSDL 69 Zuora tidied up the dates in the system to either be date only or dateTime with dateTime usually reserved for things like an object's created or updated date where the time of day may be important for reporting or issue tracking. But subscription, term and rate plan charge effective start/end dates are now all date only.
Like yourself, I too was confused when I first discovered this behavior, but again, that's how Zuora works and you need to factor this into any reporting or querying you do. A great example of this is the out of the box, MRR by Product or MRR by Account reports. The filters for the effective end date are slightly different than you'd first expect, they're not '<=' but just '<'.
Anyway, hope this helps, even though 'that's the way it is' probably wasn't what you were hoping for as an answer.