[Info-vax] enhancements to VMS MAIL in VMS 8.4

[Jan-Erik Soderholm]

Phillip Helbig---undress to reply wrote 2011-11-17 23:31:
> Can someone explain this?
>
>> 2.8 Mail Utility Enhancements
>> This section describes the mail enhancements in OpenVMS Version 8.4.
>>
>> 2.8.1 Support for More Than 255 Characters in Mail Headers
>> Support for more than 255 characters in mail headers has been added, as
>> per the RFC 2822 standard. The headers include attributes such as
>> Subject, To, CC, and F rom fields. You can now send and receive messages
>> with headers up to 998 characters.
>>
>> 2.8.2 Mail Forwarding Entry Limit Increased
>> The forward username string length has been increased from 31 to 255
>> characters.  To utilize this long username string, set bit 4 of the
>> DCL_CTLFLAGS system parameter. After this bit is set, the username
>> length is set to a maximum length of 255 characters.  Even if this bit
>> is cleared, the behavior remains unchanged, that is, the username
>> length with 255 characters is still supported. Note that the character
>> length cannot be reset to 31 characters.
>
> Does that mean that until the bit is set for the first time, the old
> behaviour applies, but after it is set, then the new behaviour, EVEN IF
> IT IS RESET TO THE OLD VALUE (i.e. the bit is cleared)?  That's how I
> parse it, but I don't see any reason for it nor how this would be
> implemented in detail.  (Does it survive a reboot?)
>

Maybe it is stored (irreverasble) somewhere in one of the .MAI files ?
Like a one-shot "convert" that can't be backed out of.
Now, the question is, has this feature any drawback ?