For PHP installations that have `mbstring.func_overload` enabled (set to a
value including `2`), the `strlen` function will be overloaded to use the
`mb_strlen` equivalent. Problematically, the internal encoding of `UTF-8`
will be applied to all file content, which will count UTF-8 characters
rather than bytes. This will cause the data to be saved correctly; however,
the `size` recorded in the %file table will be recorded incorrectly.

This patch allows the backend to report the size of the contents saved with
the request and provides a failsafe mechanism which will use the mbstring
equivalent if available, and the mbstring version is coded to use the `8bit`
as the encoding which will prevent reading characters.

References:
https://github.com/osTicket/osTicket-1.8/issues/552

This stems from a confusing similarity between the + operator for arrays
and array_merge() in php. Adding arrays will ignore items in the RHS where
keys are present in the LHS. Therefore, when adding numerically indexed
arrays together, only items on the RHS that have a key higher than the
greatest key on the LHS will be included.

It is perfectectly fine to have an image cited in an HTML body similar to:

<img width=909 height=302 src=cid:image002.jpg@01CF5426.BF5A72A0 alt=image>

Which may or may not have quoted @src attribute, and may very well have an
at sign (@) somewhere in the attribute text. The previous regular expression
would not match such a @src attribute.

It is the defacto standard to reference an inline image in an email by
referencing the Content-ID header of the referenced attachment in the @src
attribute of the image. For instance, `<imc src="cid:image001.png">` where
the `cid:` scheme of the attribute indicates that the referenced image URL
is a separate content of the email. The image attached to the email would
have an accompanying header like: `Content-Id: <image001.png>`. However,
some mail systems, including a certain fax to email service, do not
correctly indicate the location of the image with the content-id URL.
Instead, the referenced image tag would be `<img src="image001.png">`

This patch addresses the issue by searching the message body for all
references to attached content-id's in all @src attributes with or without
the content-id URL scheme indicator. Previously, such images would not be
displayed inline in the ticket thread.

References:
https://tools.ietf.org/html/rfc2392

Previously only admins and department managers could show assigned tickets
on open queue -even- when the feature is disabled globally. This pull
request extends the same previlege to all agents.

Such images are attached to emails by Lotus Notes. Technically, these images
are valid attachments, although historically osTicket would reject them

This is a regression introduced somewhere along the way in the new storage
API system for osTicket.

There are extensions such as "7z" and "gz" that are valid.

  * Administrator can disable the new activity alert
  * Administrator can disable automatic collaborators from email headers

Use `p:` in the database hostname specification, so `p:localhost` for
instance. This will help with SSL and remote database users.

References:
http://www.php.net/manual/en/mysqli.persistconns.php

It was also the last-modified date of the category -- not the actual FAQ
article itself

When checking ticket access - only consider assignment IF the ticket is
open. This is required since staff_id field is overloaded to show who closed
the ticket.

This can happen when associated department is private and the system has no
default department (which is possible with v1.6 upgrade)

The bug prevented attachments from being sent out if it was previously
attached to the ticket - for example, you could resend a file to end user.