What to choose for mail, zimbra, ispmanager or other?

Question

gmail

It turned out that e-mail correspondence was required for the trial, but according to the old Iraqi tradition, mail from the hosting company is used, thunderbird pulls mail from the server, where incoming messages are stored, as a rule, for no more than two weeks, and outgoing messages are not stored at all, naturally, that notaries cannot certify letters on users' computers.
There was a task to organize a mail service, with the storage of incoming and outgoing mail for three years.
What would you recommend for implementation?
There is a great option - mail for a domain from Yandex, large and free mailboxes, but there are many restrictions, for example, you can’t do mailing lists, and most importantly, anything can happen with this mail, from the fact that it can become paid, with a price tag not less than Google, ending with the fact that it can simply be removed.
There are mail options from Google, but it turns out there, more than 100,000 rubles a year, and this is not our level, the same thing with Masterhost, for example.
The third option is to use your server, or ISPManager, on a server in the data center where our sites are already spinning, or install a hypervisor on it and place ISPManager with sites in one virtual machine, in another, for example Zimbra, or rent a new server where to deploy Zimbra .
Or will it limit itself to buying an EDS and leave everything as it is, because in theory, if a letter is signed by a qualified EDS, this should be enough for the court and no matter where the letter is physically located?

Answer 1

Stop your VPS/Dedicated with ISPmanager/Vesta.

Answer 2

I may be wrong, but if the mail is legally important, then you should not keep the mail server, because. the interested party has full access to the server and on it you can make any changes to the logs or letters, i.e. a normal expert should not accept such evidence.
Thus, you need a mail service whose data will be authoritative and can become evidence in court. Therefore, it makes sense to work out your version with EDS.
If you just need your own server with long-term storage of letters, then Postfix, Exim from the free one under Linux or MDamon, Kerio mail server from the paid one under Windows.

Answer 3

As a practitioner with experience in litigation, I'll tell you this: it's all bullshit. The Court does not care deeply about these EDSs and all this correspondence will be uninteresting in the Court.
Variants of how it will actually be :
1. The court will unsubscribe that "there is no way to check the EDS"
2. The court will consider evidence in paper form, where the EDS is unimportant
3. There will be an examination (most likely the Court will not appoint, so on your initiative and at your expense), but
according to the results, correspondence will still not play an important role

more than 100,000 rubles a year, and this is not our level,

I conclude that the expertise will be unbearable for you, you don’t keep a tedious and competent lawyer-practitioner in legal proceedings, you won’t find money for a bribe.
I advise you to either give up on the idea in principle (I'm talking about EDS, because your own mailer is usually not bad) or open the cards and write what you want in principle and, perhaps , another way will be found.
Offhand, by the way, I'll tell you a feint with your ears. Mail is stored in a certain office (the same Yandex or any office that has a legal entity in the Russian Federation). In legal proceedings, you petition for the reclamation of evidence (you did not write - is this a civil process or something else?) from Yandex and as a result you will already have a printout of mail from a third, uninterested person. With signature and stamp. Here is such a paper in the Court is no longer what the code is cracked.