Hello, dimario31, you wrote: a C>> Minuses a zero, pluses a cloud. D> the minus nevertheless is - constant letters in support:" My key does not work "after the user rearranged system and downloaded the last version (and transited more year). In all remaining, really, one pluses. Such is not present. Therefore as wrote above, there is a state"Expired"- the key is delayed for the new version. And accordingly, it is shown to the user not as tree_bool a variable, and the torn text that to what and why, and that to use the last version to it it is necessary to prolong the license (updates) or to return to older version . The program - for the machine, a product - for the user. It is the program in itself knows about 3-eh (well generally there will be more) states: unregistered, registered, expired. And here already"product"to the user produces the torn information: what to do, why yes as. And not the message in style MessageBox, and links to update purchase at a discount, support and . D>> constant letters in support: , for years was two or three requests to give the old version. Well also produced, if asked. On mine "2-3 times for years" it is a little, in comparison with pluses of such approach which in difference "2-3 times for years" bring a profit permanently. I it not so simply tell all. This - experience. And practical. And years. Here to you a simple example of such experience. And on the theoretical logic this experience and not very much also was obvious in advance. At least theorists do not speak about it. The theory: it would seem - in the theory - in my case it is necessary to hold on the server the full archive of assembly for years that the user could be rolled away to the old version. Practice: figs! Practice says that these cases of unit for years. And they can be solved pens. And for , but not prolonged users. Unobvious experience: the archive of all for all years is necessary just to another. Namely to "partners of Golubkovym" which somewhere found a key from what-thread distribution before last on Giveawayoftheday, or filched at the neighbor. Also clarify, to what it will be . Curious experience: all it is not necessary for normal users. They write to support, and note units for years. And the question dares: it is possible to give the old version, and it is possible a key at a discount in 99 percent on the last version, but with free updates a maximum for a week. It is possible still that. But note: it already our user, and its problems - our money. Such it is not necessary to lose. Tremendous experience: because of these letters at once it becomes visible, what not so in model of sales \prolongations. Where also that to not clearly user where it is badly written where something hinders update purchase where on the contrary helps. And just such things, everyones theories you never receive. Only dialogue with live, user . At programs of problems does not happen. But they are at users. It is necessary to solve not a program problem, and a problem of the user. And then all happens absolutely differently, and to the best.