I needed a new email provider and chose sdf.org .
Their basic level uses mutt to send and receive email.
[SeaMonkey's email client can _read_ using POP3.]

Instructions are provided to setup Thunderbird [but *NOT* SeaMonkey] to
use IMAP to receive email and to send using SMTP with STARTTLS.

For my _immediate_ needs it appears reasonable to get something going
with Thunderbird. From what I read, they both nominally use MBOX files.
Is that true and do they use the same version?
Any 'gotchas' to be aware of?

Richard Owlett <rowlett@cloud85.net> wrote:

>I needed a new email provider and chose sdf.org .
>Their basic level uses mutt to send and receive email.
>[SeaMonkey's email client can _read_ using POP3.]

>Instructions are provided to setup Thunderbird [but *NOT* SeaMonkey] to
>use IMAP to receive email and to send using SMTP with STARTTLS.

>For my _immediate_ needs it appears reasonable to get something going
>with Thunderbird. From what I read, they both nominally use MBOX files.
>Is that true and do they use the same version?
>Any 'gotchas' to be aware of?

MBOXRD was Netscape's improvement to MBOXO, the dreadful format that
prepends the quote character ">" in front of From in the body of the
message, corrupting messages as they are received.

Library of Congress has a quick description:

https://www.loc.gov/preservation/digital/formats/fdd/fdd000385.shtml

As far as I know, every application that derived from Netscape keeps up
with the format and its minor variations, but I don't really know.

The trouble with MBOX was that it wasn't described adequately at the
beginning and mail clients failed to recognize reality, ignoring the need
to write an effective parsing mechanism. Parsing for a line beginning with
"From_" after a blank line was NEVER an inadequate method of parsing for
the delimiter. pine/alpine, which I use, has long created the delimiter
by essentially copying details from ENVELOPE FROM into the delimiter and
parsing for a line that looks like ENVELOPE FROM.

More that three decades later, RFC 4155 was written to define the MBOX
file format as a media type, but that didn't get all those lazily
written parsing mechanisms to get rewritten. This requires the use of
the standard time stamp.

My recollection was that MBOX was a Berkeley thing, but the Wikipedia
article reminds me that Unix 5th edition from 1974 that got released to
universities, and then development of BSD at Berkeley was kept in parallel
to Unix through the 8th edition 1985. Note that 5th edition is not the
famous commercial Unix System V from 1983. System V included BSD stuff
like MBOX and sendmail but typically we didn't use sendmail. I remember
editing mailsurr in SysVRel4, which didn't include sendmail.

On Sat, 19 Aug 2023 12:21:37 -0500, Richard Owlett wrote:

> I needed a new email provider and chose sdf.org .
> Their basic level uses mutt to send and receive email.
> [SeaMonkey's email client can _read_ using POP3.]
>
> Instructions are provided to setup Thunderbird [but *NOT* SeaMonkey] to
> use IMAP to receive email and to send using SMTP with STARTTLS.
>
> For my _immediate_ needs it appears reasonable to get something going
> with Thunderbird. From what I read, they both nominally use MBOX files.
> Is that true and do they use the same version?
> Any 'gotchas' to be aware of?

Thunderbird and SeaMonkey use the same MBOX file format for POP3
folders and Local Folders.

IMAP folders use a different MBOX file format to POP3 folders and
Local Folders.

Do not transfer MBOX files directly out of or into an IMAP account.
If you want to transfer POP3 messages across into an IMAP account,
do this instead:
* Transfer the MBOX file to a folder in Local Folders
* From within Thunderbird, move the messages from Local Folders to
the IMAP folder.

--
Kind regards
Ralph
🦊

Ralph Fox <-rf-nz-@-.invalid> wrote:
>On Sat, 19 Aug 2023 12:21:37 -0500, Richard Owlett wrote:

>>I needed a new email provider and chose sdf.org .
>>Their basic level uses mutt to send and receive email.
>>[SeaMonkey's email client can _read_ using POP3.]

>>Instructions are provided to setup Thunderbird [but *NOT* SeaMonkey] to
>>use IMAP to receive email and to send using SMTP with STARTTLS.
>>For my _immediate_ needs it appears reasonable to get something going
>>with Thunderbird. From what I read, they both nominally use MBOX files.
>>Is that true and do they use the same version?
>>Any 'gotchas' to be aware of?

>Thunderbird and SeaMonkey use the same MBOX file format for POP3
>folders and Local Folders.

>IMAP folders use a different MBOX file format to POP3 folders and
>Local Folders.

Can you explain why this would be? Is the delimiter line being used for
encoding to maintain synchronization between the local and remote folder?
Or does the local folder merely copy the delimiter in use in the remote
folder?

>. . .

Richard Owlett wrote:
> I needed a new email provider and chose sdf.org .
> Their basic level uses mutt to send and receive email.
> [SeaMonkey's email client can _read_ using POP3.]
>
> Instructions are provided to setup Thunderbird [but *NOT* SeaMonkey] to
> use IMAP to receive email and to send using SMTP with STARTTLS.
>
> For my _immediate_ needs it appears reasonable to get something going
> with Thunderbird. From what I read, they both nominally use MBOX files.
> Is that true and do they use the same version?
> Any 'gotchas' to be aware of?
>

Since Thunderbird and Seamonkey/Mail are essentially the same program,
use the Thunderbird instructions to set Seamonkey up. Seamonkey can
handle IMAP as well.
btw, you use SMTP to write - POP3 is a "read" protocol. If you want to
use Seamonkey then the fact you can't write using POP3 is really not a
problem.

Don Vito Martinelli wrote:
> Richard Owlett wrote:
>> I needed a new email provider and chose sdf.org .
>> Their basic level uses mutt to send and receive email.
>> [SeaMonkey's email client can _read_ using POP3.]
>>
>> Instructions are provided to setup Thunderbird [but *NOT* SeaMonkey] to use
>> IMAP to receive email and to send using SMTP with STARTTLS.
>>
>> For my _immediate_ needs it appears reasonable to get something going with
>> Thunderbird. From what I read, they both nominally use MBOX files.
>> Is that true and do they use the same version?
>> Any 'gotchas' to be aware of?
>>
>
> Since Thunderbird and Seamonkey/Mail are essentially the same program, use the
> Thunderbird instructions to set Seamonkey up.  Seamonkey can handle IMAP as well.
> btw, you use SMTP to write - POP3 is a "read" protocol.  If you want to use
> Seamonkey then the fact you can't write using POP3 is really not a problem.

Thunderbird diverged much after 68. If for the better someone elase can
decide. The current 2.53 line is basically 60 to 68 code and incompatible with
current Thunderbird. While we still updating central code for a possible
release based on later code it still will be diffrent beacause we will not
take changes which remoced basic functionality and rather fork some code then.
Address book comes in mind first.

FRG

On Sat, 19 Aug 2023 21:13:42 -0000 (UTC), Adam H. Kerman wrote:
> Ralph Fox <-rf-nz-@-.invalid> wrote:
>>
>> Thunderbird and SeaMonkey use the same MBOX file format for POP3
>> folders and Local Folders.
>>
>> IMAP folders use a different MBOX file format to POP3 folders and
>> Local Folders.
>
> Can you explain why this would be? Is the delimiter line being used for
> encoding to maintain synchronization between the local and remote folder?
> Or does the local folder merely copy the delimiter in use in the remote
> folder?

I can run a test in minutes which will show that IMAP folders have a
different MBOX file format and _what_ some of those differences are.
You are welcome to repeat the test yourself and compare results. See
the test details below.

As to _why_ IMAP folders have a different MBOX file format, I expect
you would need to go back over 20 years to find the design decisions
made when IMAP support was first implemented.

As for the delimiter line and the remote server. The IMAP protocol
[RFC1730, RFC2060, RFC9051] does not use MBOX file delimiter lines,
nor does it use any of the various MBOX file formats for sync. The
IMAP mail server may not even be using an MBOX file for its storage.

————————————————————————————————————————————————————————————————————

TEST DETAILS

This test shows that Thunderbird’s IMAP folders have a different
MBOX file format to Thunderbird’s POP3 folders and “Local Folders”
folders. Specifically, it demonstrates that Thunderbird’s IMAP
folders use a different “From ” quoting rule to Thunderbird’s POP3
folders and “Local Folders” folders.

I emailed myself a message where the message body contains lines
beginning with “From ”, “>From ”, and “>>From ”. For this test the
message *source* must contain lines beginning with “From ”, “>From ”,
and “>>From ”. To that end, the following are important:

  1)  The message must _not_ use format=flowed.

      Format=flowed will change lines beginning with “From ” to lines
      beginning with “ From ”, using reversible space-stuffing.
      This reversible space-stuffing is a property of format=flowed
      [RFC2646 ss. 4.1 + 4.4, RFC3676 ss. 4.2 + 4.4], not a property
      of the MBOX file format. Messages which are not format=flowed
      do not have space-stuffing in an MBOX file, and format=flowed
      messages have this space-stuffing even when they are not in an
      MBOX file.

  2)  The message must be sent with 7bit or 8bit content transfer
      encoding. The message must _not_ use quoted-printable.

      Quoted-printable will change lines beginning with “From ” to
      lines beginning with “=46rom ” [RFC2049 s. 3(8)]. An email
      program which can decode quoted-printable (and most all can)
      will decode the “=46” back to “F” when displaying the email.

  3)  The message should not be sent from an email program which uses
      an MBOX file format as its own native storage format.

      This is to avoid the chance of introducing “From ” quoting at
      the sender.

To that end, I sent myself the email below from Forté Agent 8.00.
  1)  Forté Agent does not do format=flowed.
  2)  Quoted-printable was turned off for sending this email.
      In Forté Agent I can turn off sending quoted-printable on a
      message-by-message basis.
  3)  Forté Agent’s own native file format is not an MBOX file format.

This screen-shot shows the email I sent in Forté Agent.

    screen-shot: <http://img4.imagetitan.com/img.php?image=26_ubrba6_1__original_sent_message.png>

Thunderbird IMAP:

    When I downloaded the email into an IMAP account in Thunderbird,
    the IMAP MBOX file and the rendered email message looked like so:

    screen-shot: <http://img4.imagetitan.com/img.php?image=26_ubrba6_2__thunderbird_imap_folder.png>

    As you can see, there is no “From ” quoting. The email body line
    beginning “From ” still begins with “From ” in the IMAP MBOX file.

    This looks similar to the MBOXCL2 file format. But unlike MBOXCL2
    there is no “Content-Length:” header. If there is a Content-Length
    field somewhere which tells the message’s length, this would appear
    to be stored in metadata outside the MBOX file.

Thunderbird POP3:

    When I downloaded the same email into a POP3 account in Thunderbird,
    the POP3 MBOX file and the rendered email message looked like so:

    screen-shot: <http://img4.imagetitan.com/img.php?image=26_ubrba6_3__thunderbird_pop3_inbox.png>

    As you can see, there is non-reversible “From ” quoting. “From ”
    and “>From ” in the sent email both appear as “>From ” in the
    POP3 MBOX file.

    This looks like the MBOXO file format.

Thunderbird Local Folders

    As a further test I copied this email from the IMAP folder into
    a folder in Local Folders. This was to see if the “From ” quoting
    changed going from IMAP to Local Folders. In Local Folders, the
    folder MBOX file and rendered email looked like so:

    screen-shot: <http://img4.imagetitan.com/img.php?image=26_ubrba6_4__thunderbird_local_folders.png>

    As you can see, this looks the same as POP3 with non-reversible
    “From ” quoting.

    This also looks like the MBOXO file format.

One other difference you will see between Thunderbird’s MBOX files for
POP3 and IMAP.

   *  POP3:  Emails received in Thunderbird’s POP3 Inbox have extra
      headers added by Thunderbird with message status metadata.
          X-Mozilla-Status:
          X-Mozilla-Status2:
          X-Mozilla-Keys:

   *  IMAP:  Emails received in Thunderbird’s IMAP account folders do
      not have any extra headers added by Thunderbird.

      The message in an IMAP MBOX file appears to be an verbatim copy
      of the message on the sever, with no “From ” quoting and no
      added headers. One could speculate that a design decision was
      made over 20 years ago in order to simplify the implementation
      of _bidirectional_ sync for IMAP.

—————————————————————————————————————————————————————————————————————

--
Kind regards
Ralph Fox

𒊮 𒁉 𒍣 𒂵 𒉺 𒉆 𒈨

Ralph Fox <-rf-nz-@-.invalid> wrote:
>On Sat, 19 Aug 2023 21:13:42 -0000 (UTC), Adam H. Kerman wrote:
>>Ralph Fox <-rf-nz-@-.invalid> wrote:

>>>Thunderbird and SeaMonkey use the same MBOX file format for POP3
>>>folders and Local Folders.

>>>IMAP folders use a different MBOX file format to POP3 folders and
>>>Local Folders.

>>Can you explain why this would be? Is the delimiter line being used for
>>encoding to maintain synchronization between the local and remote folder?
>>Or does the local folder merely copy the delimiter in use in the remote
>>folder?

>I can run a test in minutes which will show that IMAP folders have a
>different MBOX file format and _what_ some of those differences are.
>You are welcome to repeat the test yourself and compare results. See
>the test details below.

Thanks for the interesting information.

>As to _why_ IMAP folders have a different MBOX file format, I expect
>you would need to go back over 20 years to find the design decisions
>made when IMAP support was first implemented.

I was just guessing that it had something to do with synchronization but
I really don't see why the delimiter line would be used for that
purpose.

>As for the delimiter line and the remote server. The IMAP protocol
>[RFC1730, RFC2060, RFC9051] does not use MBOX file delimiter lines,
>nor does it use any of the various MBOX file formats for sync. The
>IMAP mail server may not even be using an MBOX file for its storage.

Of course there was no RFC for a storage format, as it wasn't a network
compatibility issue.

>. . .

On 08/19/2023 12:21 PM, Richard Owlett wrote:
> I needed a new email provider and chose sdf.org .
> Their basic level uses mutt to send and receive email.
> [SeaMonkey's email client can _read_ using POP3.]
>
> Instructions are provided to setup Thunderbird [but *NOT* SeaMonkey] to
> use IMAP to receive email and to send using SMTP with STARTTLS.
>
> For my _immediate_ needs it appears reasonable to get something going
> with Thunderbird. From what I read, they both nominally use MBOX files.
> Is that true and do they use the same version?
> Any 'gotchas' to be aware of?
>

I thought I was asking a simple straight forward question ;{

External *FIXED* constraints require:
- use Thunderbird to read a certain server
- use only IMAP to read those emails

Having used SeaMonkey as my email client for many years and wishing to
continue to use accumulated sorting/labeling rules, I have created an
empty folder under the "Inbox" folder titled "imported-emails".

Can Thunderbird create a SeaMonkey readable object to be placed in
folder "imported-emails"?

TIA

On Mon, 21 Aug 2023 10:23:12 -0500, Richard Owlett wrote:

> On 08/19/2023 12:21 PM, Richard Owlett wrote:
>> I needed a new email provider and chose sdf.org .
>> Their basic level uses mutt to send and receive email.
>> [SeaMonkey's email client can _read_ using POP3.]
>>
>> Instructions are provided to setup Thunderbird [but *NOT* SeaMonkey] to
>> use IMAP to receive email and to send using SMTP with STARTTLS.
>>
>> For my _immediate_ needs it appears reasonable to get something going
>> with Thunderbird. From what I read, they both nominally use MBOX files.
>> Is that true and do they use the same version?
>> Any 'gotchas' to be aware of?
>>
>
> I thought I was asking a simple straight forward question ;{
>
> External *FIXED* constraints require:
> - use Thunderbird to read a certain server
> - use only IMAP to read those emails
>
> Having used SeaMonkey as my email client for many years and wishing to
> continue to use accumulated sorting/labeling rules, I have created an
> empty folder under the "Inbox" folder titled "imported-emails".
>
> Can Thunderbird create a SeaMonkey readable object to be placed in
> folder "imported-emails"?

The MBOX file from a Thunderbird *IMAP* account is not SeaMonkey readable.
It may partly work. But only partly.

To create a SeaMonkey readable object, do this:

1. In Thunderbird,
1.1 Create a folder "exported-emails" in Local Folders
1.2 Copy those IMAP emails into the folder "exported-emails" in
Thunderbird's Local Folders.

2. Whether the Thunderbird MBOX file for "exported-emails" is
SeaMonkey readable or not will depend on _where_ in SeaMonkey
you place it.

2.1 If you place it in a POP3 account or in Local Folders
in SeaMonkey, it will be SeaMonkey readable.

2.2 If you place it in an IMAP account in SeaMonkey, it will
not be SeaMonkey readable.

I presume your SeaMonkey folder "imported-emails" would be in
category 2.1, but that is not for me to confirm.

--
Kind regards
Ralph Fox
🦊

On 08/21/2023 04:15 PM, Ralph Fox wrote:
> On Mon, 21 Aug 2023 10:23:12 -0500, Richard Owlett wrote:
>
>> On 08/19/2023 12:21 PM, Richard Owlett wrote:
>>> I needed a new email provider and chose sdf.org .
>>> Their basic level uses mutt to send and receive email.
>>> [SeaMonkey's email client can _read_ using POP3.]
>>>
>>> Instructions are provided to setup Thunderbird [but *NOT* SeaMonkey] to
>>> use IMAP to receive email and to send using SMTP with STARTTLS.
>>>
>>> For my _immediate_ needs it appears reasonable to get something going
>>> with Thunderbird. From what I read, they both nominally use MBOX files.
>>> Is that true and do they use the same version?
>>> Any 'gotchas' to be aware of?
>>>
>>
>> I thought I was asking a simple straight forward question ;{
>>
>> External *FIXED* constraints require:
>> - use Thunderbird to read a certain server
>> - use only IMAP to read those emails
>>
>> Having used SeaMonkey as my email client for many years and wishing to
>> continue to use accumulated sorting/labeling rules, I have created an
>> empty folder under the "Inbox" folder titled "imported-emails".
>>
>> Can Thunderbird create a SeaMonkey readable object to be placed in
>> folder "imported-emails"?
>
>
> The MBOX file from a Thunderbird *IMAP* account is not SeaMonkey readable.
> It may partly work. But only partly.
>
> To create a SeaMonkey readable object, do this:
>
> 1. In Thunderbird,
> 1.1 Create a folder "exported-emails" in Local Folders
> 1.2 Copy those IMAP emails into the folder "exported-emails" in
> Thunderbird's Local Folders.
>
> 2. Whether the Thunderbird MBOX file for "exported-emails" is
> SeaMonkey readable or not will depend on _where_ in SeaMonkey
> you place it.
>
> 2.1 If you place it in a POP3 account or in Local Folders
> in SeaMonkey, it will be SeaMonkey readable.
>
> 2.2 If you place it in an IMAP account in SeaMonkey, it will
> not be SeaMonkey readable.
>
> I presume your SeaMonkey folder "imported-emails" would be in
> category 2.1, but that is not for me to confirm.
>
>

Thank you for your reply.
I've got some weird local problem that I'll need physically local help
to diagnose. I've helped enough newbies in the past decades to know when
I'm missing something ;/