CHANGED FROM 3.1b TO 3.1c

* Fix a stack overflow on colon-separated CSI parsing.

CHANGES FROM 3.1a TO 3.1b

* Fix build on systems without sys/queue.h.

* Fix crash when allow-rename is on and an empty name is set.

CHANGES FROM 3.1 TO 3.1a

* Do not close stdout prematurely in control mode since it is needed to print
  exit messages. Prevents hanging when detaching with iTerm2.

CHANGES FROM 3.0a TO 3.1

* Only search the visible part of the history when marking (highlighting)
  search terms. This is much faster than searching the whole history and solves
  problems with large histories. The count of matches shown is now the visible
  matches rather than all matches.

* Search using regular expressions in copy mode. search-forward and
  search-backward use regular expressions by default; the incremental versions
  do not.

* Turn off mouse mode 1003 as well as the rest when exiting.

* Add selection_active format for when the selection is present but not moving
  with the cursor.

* Fix dragging with modifier keys, so binding keys such as C-MouseDrag1Pane and
  C-MouseDragEnd1Pane now work.

* Add -a to list-keys to also list keys without notes with -N.

* Do not jump to next word end if already on a word end when selecting a word;
  fixes select-word with single character words and vi(1) keys.

* Fix top and bottom pane calculation with pane border status enabled.

* Add support for adding a note to a key binding (with bind-key -N) and use
  this to add descriptions to the default key bindings. A new -N flag to
  list-keys shows key bindings with notes. Change the default ? binding to use
  this to show a readable summary of keys. Also extend command-prompt to return
  the name of the key pressed and add a default binding (/) to show the note
  for the next key pressed.

* Add support for the iTerm2 DSR 1337 sequence to get the terminal version.

* Treat plausible but invalid keys (like C-BSpace) as literal like any other
  unrecognised string passed to send-keys.

* Detect iTerm2 and enable use of DECSLRM (much faster with horizontally split
  windows).

* Add -Z to default switch-client command in tree mode.

* Add ~ to quoted characters for %%%.

* Document client exit messages in the manual page.

* Do not let read-only clients limit the size, unless all clients are
  read-only.

* Add a number of new formats to inspect what sessions and clients a window is
  present or active in.

* Change file reading and writing to go through the client if necessary. This
  fixes commands like "tmux loadb /dev/fd/X". Also modify source-file to
  support "-" for standard input, like load-buffer and save-buffer.

* Add ~/.config/tmux/tmux.conf to the default search path for configuration
  files.

* Bump the escape sequence timeout to five seconds to allow for longer
  legitimate sequences.

* Make a best effort to set xpixel and ypixel for each pane and add formats for
  them.

* Add push-default to status-left and status-right in status-format[0].

* Do not clear search marks on cursor movement with vi(1) keys.

* Add p format modifier for padding to width and allow multiple substitutions
  in a single format.

* Add -f for full size to join-pane (like split-window).

* Do not use bright when emulating 256 colours on an 8 colour terminal because
  it is also bold on some terminals.

* Make select-pane -P set window-active-style also to match previous behaviour.

* Do not truncate list-keys output.

* Turn automatic-rename back on if the \033k rename escape sequence is used
  with an empty name.

* Add support for percentage sizes for resize-pane ("-x 10%"). Also change
  split-window and join-pane -l to accept similar percentages and deprecate the
  -p flag.

* Add -F flag to send-keys to expand formats in search-backward and forward
  copy mode commands and copy_cursor_word and copy_cursor_line formats for word
  and line at cursor in copy mode. Use for default # and * binding with vi(1)
  keys.

* Add formats for word and line at cursor position in copy mode.

* Add formats for cursor and selection position in copy mode.

* Support all the forms of RGB colour strings in OSC sequences rather than
  requiring two digits.

* Limit lazy resize to panes in attached sessions only.

* Add an option to set the key sent by backspace for those whose system uses ^H
  rather than ^?.

* Change new-session -A without a session name (that is, no -s option also) to
  attach to the best existing session like attach-session rather than a new
  one.

* Add a "latest" window-size option which tries to size windows based on the
  most recently used client. This is now the default.

* Add simple support for OSC 7 (result is available in the pane_path format).

* Add push-default and pop-default for styles which change the colours and
  attributes used for #[default]. These are used in status-format to restore
  the behaviour of window-status-style being the default for
  window-status-format.

* Add window_marked_flag.

* Add cursor-down-and-cancel in copy mode.

* Default to previous search string for search-forward and search-backward.

* Add -Z flag to rotate-window, select-pane, swap-pane, switch-client to
  preserve zoomed state.

* Add -N to capture-pane to preserve trailing spaces.

* Add reverse sorting in tree, client and buffer modes.

CHANGES FROM 3.0 TO 3.0a

* Do not require REG_STARTEND.

* Respawn panes or windows correctly if default-command is set.

* Add missing option for after-kill-pane hook.

* Fix for crash with a format variable that doesn't exist.

* Do not truncate list-keys output on some platforms.

* Do not crash when restoring a layout with only one pane.

CHANGES FROM 2.9 TO 3.0

* Workaround invalid layout strings generated by older tmux versions and add
  some additional sanity checks

* xterm 348 now disables margins when resized, so send DECLRMM again after
  resize.

* Add support for the SD (scroll down) escape sequence.

* Expand arguments to C and s format modifiers to match the m modifier.

* Add support for underscore colours (Setulc capability must be added with
  terminal-overrides as described in tmux(1)).

* Add a "fill" style attribute for the fill colour of the drawing area (where
  appropriate).

* New -H flag to send-keys to send literal keys.

* Format variables for pane mouse modes (mouse_utf8_flag and mouse_sgr_flag)
  and for origin mode (origin_flag).

* Add -F to refresh-client for flags for control mode clients, only one flag
  (no-output) supported at the moment.

* Add a few vi(1) keys for menus.

* Add pane options, set with set-option -p and displayed with show-options -p.
  Pane options inherit from window options (so every pane option is also
  a window option). The pane style is now configured by setting window-style
  and window-active-style in the pane options; select-pane -P and -g now change
  the option but are no longer documented.

* Do not document set-window-option and show-window-options. set-option -w and
  show-options -w should be used instead.

* Add a -A flag to show-options to show parent options as well (they are marked
  with a *).

* Resize panes lazily - do not resize unless they are in an attached, active
  window.

* Add regular expression support for the format search, match and substitute
  modifiers and make them able to ignore case. find-window now accepts -r to
  use regular expressions.

* Do not use $TMUX to find the session because for windows in multiple sessions
  it is wrong as often as it is right, and for windows in one session it is
  pointless. Instead use TMUX_PANE if it is present.

* Do not always resize the window back to its original size after applying a
  layout, keep it at the layout size until it must be resized (for example when
  attached and window-size is not manual).

* Add new-session -X and attach-session -x to send SIGHUP to parent when
  detaching (like detach-client -P).

* Support for octal escapes in strings (such as \007) and improve list-keys
  output so it parses correctly if copied into a configuration file.

* INCOMPATIBLE: Add a new {} syntax to the configuration file. This is a string
  similar to single quotes but also includes newlines and allows commands that
  take other commands as string arguments to be expressed more clearly and
  without additional escaping.

  A literal { and } or a string containing { or } must now be escaped or
  quoted, for example '{' and '}' instead of { or }, or 'X#{foo}' instead of
  X#{foo}.

* New <, >, <= and >= comparison operators for formats.

* Improve escaping of special characters in list-keys output.

* INCOMPATIBLE: tmux's configuration parsing has changed to use yacc(1). There
  is one incompatible change: a \ on its own must be escaped or quoted as
  either \\ or '\' (the latter works on older tmux versions).

  Entirely the same parser is now used for parsing the configuration file
  and for string commands. This means that constructs previously only
  available in .tmux.conf, such as %if, can now be used in string commands
  (for example, those given to if-shell - not commands invoked from the
  shell, they are still parsed by the shell itself).

* Add support for the overline attribute (SGR 53). The Smol capability is
  needed in terminal-overrides.

* Add the ability to create simple menus. Introduces new command
  display-menu. Default menus are bound to MouseDown3 on the status line;
  MouseDown3 or M-MouseDown3 on panes; MouseDown3 in tree, client and
  buffer modes; and C-b < and >.

* Allow panes to be empty (no command). They can be created either by piping to
  split-window -I, or by passing an empty command ('') to split-window. Output
  can be sent to an existing empty window with display-message -I.

* Add keys to jump between matching brackets (emacs C-M-f and C-M-b, vi %).

* Add a -e flag to new-window, split-window, respawn-window, respawn-pane to
  pass environment variables into the newly created process.

* Hooks are now stored in the options tree as array options, allowing them to
  have multiple separate commands. set-hook and show-hooks remain but
  set-option and show-options can now also be used (show-options will only show
  hooks if given the -H flag). Hooks with multiple commands are run in index
  order.

* Automatically scroll if dragging to create a selection with the mouse and the
  cursor reaches the top or bottom line.

* Add -no-clear variants of copy-selection and copy-pipe which do not clear the
  selection after copying. Make copy-pipe clear the selection by default to be
  consistent with copy-selection.

* Add an argument to copy commands to set the prefix for the buffer name, this
  (for example) allows buffers for different sessions to be named separately.

* Update session activity on focus event.

* Pass target from source-file into the config file parser so formats in %if
  and %endif have access to more useful variables.

* Add the ability to infer an option type (server, session, window) from its
  name to show-options (it was already present in set-option).

CHANGES FROM 2.9 TO 2.9a

* Fix bugs in select-pane and the main-horizontal and main-vertical layouts.

CHANGES FROM 2.8 TO 2.9

* Attempt to preserve horizontal cursor position as well as vertical with
  reflow.

* Rewrite main-vertical and horizontal and change layouts to better handle the
  case where all panes won't fit into the window size, reduce problems with
  pane border status lines and fix other bugs mostly found by Thomas Sattler.

* Add format variables for the default formats in the various modes
  (tree_mode_format and so on) and add a -a flag to display-message to list
  variables with values.

* Add a -v flag to display-message to show verbose messages as the format is
  parsed, this allows formats to be debugged

* Add support for HPA (\033[`).

* Add support for origin mode (\033[?6h).

* No longer clear history on RIS.

* Extend the #[] style syntax and use that together with previous format
  changes to allow the status line to be entirely configured with a single
  option.

  Now that it is possible to configure their content, enable the existing code
  that lets the status line be multiple lines in height. The status option can
  now take a value of 2, 3, 4 or 5 (as well as the previous on or off) to
  configure more than one line. The new status-format array option configures
  the format of each line, the default just references the existing status-*
  options, although some of the more obscure status options may be eliminated
  in time.

  Additions to the #[] syntax are: "align" to specify alignment (left, centre,
  right), "list" for the window list and "range" to configure ranges of text
  for the mouse bindings.

  The "align" keyword can also be used to specify alignment of entries in tree
  mode and the pane status lines.

* Add E: and T: format modifiers to expand a format twice (useful to expand the
  value of an option).

* The individual -fg, -bg and -attr options have been removed; they
  were superseded by -style options in tmux 1.9.

* Allow more than one mode to be opened in a pane. Modes are kept on a stack
  and retrieved if the same mode is entered again. Exiting the active mode goes
  back to the previous one.

* When showing command output in copy mode, call it view mode instead (affects
  pane_mode format).

* Add -b to display-panes like run-shell.

* Handle UTF-8 in word-separators option.

* New "terminal" colour allowing options to use the terminal default colour
  rather than inheriting the default from a parent option.

* Do not move the cursor in copy mode when the mouse wheel is used.

* Use the same working directory rules for jobs as new windows rather than
  always starting in the user's home.

* Allow panes to be one line or column in size.

* Go to last line when goto-line number is out of range in copy mode.

* Yank previously cut text if any with C-y in the command prompt, only use the
  buffer if no text has been cut.

* Add q: format modifier to quote shell special characters.

* Add StatusLeft and StatusRight mouse locations (keys such as
  MouseDown1StatusLeft) for the status-left and status-right areas of the
  status line.

* Add -Z to find-window.

* Support for windows larger than the client. This adds two new options,
  window-size and default-size, and a new command, resize-window. The
  force-width and force-height options and the session_width and session_height
  formats have been removed.

  The new window-size option tells tmux how to work out the size of windows:
  largest means it picks the size of the largest session, smallest the smallest
  session (similar to the old behaviour) and manual means that it does not
  automatically resize windows. aggressive-resize modifies the choice of
  session for largest and smallest as it did before.

  If a window is in a session attached to a client that is too small, only part
  of the window is shown. tmux attempts to keep the cursor visible, so the part
  of the window displayed is changed as the cursor moves (with a small delay,
  to try and avoid excess redrawing when applications redraw status lines or
  similar that are not currently visible).

  Drawing windows which are larger than the client is not as efficient as those
  which fit, particularly when the cursor moves, so it is recommended to avoid
  using this on slow machines or networks (set window-size to smallest or
  manual).

  The resize-window command can be used to resize a window manually. If it is
  used, the window-size option is automatically set to manual for the window
  (undo this with "setw -u window-size"). resize-window works in a similar way
  to resize-pane (-U -D -L -R -x -y flags) but also has -a and -A flags. -a
  sets the window to the size of the smallest client (what it would be if
  window-size was smallest) and -A the largest.

  For the same behaviour as force-width or force-height, use resize-window -x
  or -y.

  If the global window-size option is set to manual, the default-size option is
  used for new windows. If -x or -y is used with new-session, that sets the
  default-size option for the new session.

  The maximum size of a window is 10000x10000. But expect applications to
  complain and higher memory use if making a window that big. The minimum size
  is the size required for the current layout including borders.

  The refresh-client command can be used to pan around a window, -U -D -L -R
  moves up, down, left or right and -c returns to automatic cursor
  tracking. The position is reset when the current window is changed.

CHANGES FROM 2.7 TO 2.8

* Make display-panes block the client until a pane is chosen or it
  times out.

* Clear history on RIS like most other terminals do.

* Add an "Any" key to run a command if a key is pressed that is not
  bound in the current key table.

* Expand formats in load-buffer and save-buffer.

* Add a rectangle_toggle format.

* Add set-hook -R to run a hook immediately.

* Add README.ja.

* Add pane focus hooks.

* Allow any punctuation as separator for s/x/y not only /.

* Improve resizing with the mouse (fix resizing the wrong pane in some
  layouts, and allow resizing multiple panes at the same time).

* Allow , and } to be escaped in formats as #, and #}.

* Add KRB5CCNAME to update-environment.

* Change meaning of -c to display-message so the client is used if it
  matches the session given to -t.

* Fixes to : form of SGR.

* Add x and X to choose-tree to kill sessions, windows or panes.

CHANGES FROM 2.6 TO 2.7

* Remove EVENT_* variables from environment on platforms where tmux uses them
  so they do not pass on to panes.

* Fixes for hooks at server exit.

* Remove SGR 10 (was equivalent to SGR 0 but no other terminal seems to do
  this).

* Expand formats in window and session names.

* Add -Z flag to choose-tree, choose-client, choose-buffer to automatically
  zoom the pane when the mode is entered and unzoom when it exits, assuming the
  pane is not already zoomed. This is now part of the default key bindings.

* Add C-g to exit modes with emacs keys.

* Add exit-empty option to exit server if no sessions (defaults to on).

* Show if a filter is present in choose modes.

* Add pipe-pane -I to to connect stdin of the child process.

* Performance improvements for reflow.

* Use RGB terminfo(5) capability to detect RGB colour terminals (the existing
  Tc extension remains unchanged).

* Support for ISO colon-separated SGR sequences.

* Add select-layout -E to spread panes out evenly (bound to E key).

* Support wide characters properly when reflowing.

* Pass PWD to new panes as a hint to shells, as well as calling chdir().

* Performance improvements for the various choose modes.

* Only show first member of session groups in tree mode (-G flag to choose-tree
  to show all).

* Support %else in config files to match %if; from Brad Town in GitHub issue
  1071.

* Fix "kind" terminfo(5) capability to be S-Down not S-Up.

* Add a box around the preview label in tree mode.

* Show exit status and time in the remain-on-exit pane text; from Timo
  Boettcher in GitHub issue 1103.

* Correctly use pane-base-index in tree mode.

* Change the allow-rename option default to off.

* Support for xterm(1) title stack escape sequences (GitHub issue 1075 from
  Brad Town).

* Correctly remove padding cells to fix a UTF-8 display problem (GitHub issue
  1090).

CHANGES FROM 2.5 TO 2.6, 05 October 2017

* Add select-pane -T to set pane title.

* Fix memory leak when lines with BCE are removed from history.

* Fix (again) the "prefer unattached" behaviour of attach-session.

* Reorder how keys are checked to allow keys to be specified that have a
  leading escape. GitHub issue 1048.

* Support REP escape sequence (\033[b).

* Run alert hooks based on options rather than always, and allow further bells
  even if there is an existing bell.

* Add -d flag to display-panes to override display-panes-time.

* Add selection_present format when in copy mode (allows key bindings that do
  something different if there is a selection).

* Add pane_at_left, pane_at_right, pane_at_top and pane_at_bottom formats.

* Make bell, activity and silence alerting more consistent by: removing the
  bell-on-alert option; adding activity-action and silence-action options with
  the same possible values as the existing bell-action; adding a "both" value
  for the visual-bell, visual-activity and visual-silence options to trigger
  both a bell and a message.

* Add a pane_pipe format to show if pipe-pane is active.

* Block signals between forking and resetting signal handlers so that the
  libevent signal handler doesn't get called in the child and incorrectly write
  into the signal pipe that it still shares with the parent. GitHub issue 1001.

* Allow punctuation in pane_current_command.

* Add -c for respawn-pane and respawn-window.

* Wait for any remaining data to flush when a pane is closed while pipe-pane is
  in use.

* Fix working out current client with no target. GitHub issue 995.

* Try to fallback to C.UTF-8 as well as en_US.UTF-8 when looking for a UTF-8
  locale.

* Add user-keys option for user-defined key escape sequences (mapped to User0
  to User999 keys).

* Add pane-set-clipboard hook.

* FAQ file has moved out of repository to online.

* Fix problem with high CPU usage when a client dies unexpectedly. GitHub issue
  941.

* Do a dance on OS X 10.10 and above to return tmux to the user namespace,
  allowing access to the clipboard.

* Do not allow escape sequences which expect a specific terminator (APC, DSC,
  OSC) to wait for forever - use a small timeout. This reduces the chance of
  the pane locking up completely when sent garbage (cat /dev/random or
  similar).

* Support SIGUSR2 to toggle logging on a running server, also generate the
  "out" log file with -vv not -vvvv.

* Make set-clipboard a three state option: on (tmux both sends to outside
  terminal and accepts from applications inside); external (tmux sends outside
  but does not accept inside); and off.

* Fix OSC 4 palette setting for bright foreground colours. GitHub issue 954.

* Use setrgbf and setrgbb terminfo(5) capabilities to set RGB colours, if they
  are available. (Tc is still supported as well.)

* Fix redrawing panes when they are resized several times but end up with the
  size unchanged (for example, splitw/resizep -Z/breakp).

* Major rewrite of choose mode. Now includes preview, sorting, searching and
  tagging; commands that can be executed directly from the mode (for example,
  to delete one or more buffers); and filtering in tree mode.

* choose-window and choose-session are now aliases of choose-tree (in the
  command-alias option).

* Support OSC 10 and OSC 11 to set foreground and background colours.

* Check the U8 capability to determine whether to use UTF-8 line drawing
  characters for ACS.

* Some missing notifications for layout changes.

* Control mode clients now do not affect session sizes until they issue
  refresh-client -C. new-session -x and -y works with control clients even if
  the session is not detached.

* All new sessions that are unattached (whether with -d or started with no
  terminal) are now created with size 80 x 24. Whether the status line is on or
  off does not affect the size of new sessions until they are attached.

* Expand formats in option names and add -F flag to expand them in option values.

* Remember the search string for a pane even if copy mode is exited and entered
  again.

* Some further BCE fixes (scroll up, reverse index).

* Improvements to how terminals are cleared (entirely or partially).

CHANGES FROM 2.4 TO 2.5, 09 May 2017

* Reset updated flag when restarting #() command so that new output is properly
  recognised. GitHub issue 922.

* Fix ECH with a background colour.

* Do not rely on the terminal not moving the cursor after DL or EL.

* Fix send-keys and send-prefix in copy-mode (so C-b C-b works). GitHub issue
  905.

* Set the current pane for rotate-window so it works in command sequences.

* Add pane_mode format.

* Differentiate M-Up from Escape+Up when possible (that is, in terminals with
  xterm(1) style function keys). GitHub issue 907.

* Add session_stack and window_stack_index formats.

* Some new control mode notifications and corresponding hooks:
  pane-mode-changed, window-pane-changed, client-session-changed,
  session-window-changed.

* Format pane_search_string for last search term while in copy mode (useful
  with command-prompt -I).

* Fix a problem with high CPU usage and multiple clients with #(). GitHub issue
  889.

* Fix UTF-8 combining characters in column 0.

* Fix reference counting so that panes are properly destroyed and their
  processes killed.

* Clamp SU (CSI S) parameter to work around a bug in Konsole.

* Tweak line wrapping in full width panes to play more nicely with terminal
  copy and paste.

* Fix when we emit SGR 0 in capture-pane -e.

* Do not change TERM until after config file parsing has finished, so that
  commands run inside the config file can use it to make decisions (typically
  about default-terminal).

* Make the initial client wait until config file parsing has finished to avoid
  racing with commands.

* Fix core when if-shell fails.

* Only use ED to clear screen if the pane is at the bottom.

* Fix multibyte UTF-8 output.

* Code improvements around target (-t) resolution.

* Change how the default target (for commands without -t) is managed across
  command sequences: now it is set up at the start and commands are required
  to update it if needed. Fixes binding command sequences to mouse keys.

* Make if-shell from the config file work correctly.

* Change to always check the root key table if no binding is found in the
  current table (prefix table or copy-mode table or whatever). This means that
  root key bindings will take effect even in copy mode, if not overridden by a
  copy mode key binding.

* Fix so that the history file works again.

* Run config file without a client rather than using the first client, restores
  previous behaviour.

* If a #() command doesn't exit, continue to read from it and use its last full
  line of output.

* Handle slow terminals and fast output better: when the amount of data
  outstanding gets too large, discard output until it is drained and we are
  able to do a full redraw. Prevents tmux sitting on a huge buffer that the
  terminal will take forever to consume.

* Do not redraw a client unless we realistically think it can accept the data -
  defer redraws until the client has nothing else waiting to write.

CHANGES FROM 2.3 TO 2.4, 20 April 2017

Incompatible Changes
====================

* Key tables have undergone major changes. Mode key tables are no longer
  separate from the main key tables. All mode key tables have been removed,
  together with the -t flag to bind-key and unbind-key.

  The emacs-edit, vi-edit, emacs-choose and vi-choose tables have been replaced
  by fixed key bindings in the command prompt and choose modes. The mode-keys
  and status-keys options remain.

  The emacs-copy and vi-copy tables have been replaced by the copy-mode and
  copy-mode-vi tables. Commands are sent using the -X and -N flags to
  send-keys. So the following:

    bind -temacs-copy C-Up scroll-up
    bind -temacs-copy -R5 WheelUpPane scroll-up

  Becomes:

    bind -Tcopy-mode C-Up send -X scroll-up
    bind -Tcopy-mode WheelUpPane send -N5 -X scroll-up

  These changes allows the full command parser (including command sequences) and
  command set to be used - for example, the normal command prompt with editing
  and history is now used for searching, jumping, and so on instead of a custom
  one. The default C-r binding is now:

    bind -Tcopy-mode C-r command-prompt -i -p'search up' "send -X search-backward-incremental '%%'"

  There are also some new commmands available with send -X, such as
  copy-pipe-and-cancel.
* set-remain-on-exit has gone -- can be achieved with hooks instead.
* Hooks: before hooks have been removed and only a selection of commands now
  have after hooks (they are no longer automatic). Additional hooks have been
  added.
* The xterm-keys option now defaults to on.

Normal Changes
==============

* Support for mouse double and triple clicks.
* BCE (Background Colour Erase) is now supported.
* All occurrences of a search string in copy mode are now highlighted;
  additionally, the number of search results is displayed. The highlighting
  updates interactively with the default emacs key bindings (incremental
  search).
* source-file now understands glob patterns.
* Formats now have simple comparisons:

    #{==:a,b}
    #{!=:a,b}

* There are the following new formats:

  - #{version} -- the tmux server version;
  - #{client_termtype} -- the terminal type of the client;
  - #{client_name} -- the name of a client;
  - #{client_written} -- the number of bytes written to the client.

* The configuration file now accepts %if/%endif conditional blocks which are
  processed when it is parsed; the argument is a format string (useful with the
  new format comparison options).
* detach-client now has -E to execute a command replacing the client instead of
  exiting.
* Add support for custom command aliases, this is an array option which
  contains items of the form "alias=command". This is consulted when an
  unknown command is parsed.
* break-pane now has -n to specify the new window name.
* OSC 52 support has been added for programs inside tmux to set a tmux buffer.
* The mouse "all event" mode (1003) is now supported.
* Palette setting is now possible (OSC 4 and 104).
* Strikethrough support (a recent terminfo is required).
* Grouped sessions can now be named (new -t).
* terminal-overrides and update-environment are now array options (the previous
  set -ag syntax should work without change).
* There have been substantial performance improvements.

CHANGES FROM 2.2 TO 2.3, 29 September 2016

Incompatible Changes
====================

None.

Normal Changes
==============

* New option 'pane-border-status' to add text in the pane borders.
* Support for hooks on commands: 'after' and 'before' hooks.
* 'source-file' understands '-q' to suppress errors for nonexistent files.
* Lots of UTF8 improvements, especially on MacOS.
* 'window-status-separator' understands #[] expansions.
* 'split-window' understands '-f' for performing a full-width split.
* Allow report count to be specified when using 'bind-key -R'.
* 'set -a' for appending to user options (@foo) is now supported.
* 'display-panes' can now accept a command to run, rather than always
  selecting the pane.

CHANGES FROM 2.1 TO 2.2, 10 April 2016

Incompatible Changes
====================

* The format strings which referenced time have been removed.  Instead:

  #{t:window_activity}

can be used.

* Support for TMPDIR has been removed.  Use TMUX_TMPDIR instead.
* UTF8 detection now happens automatically if the client supports it, hence
  the:

  mouse-utf8
  utf8

  options has been removed.
* The:

  mouse_utf8_flag

  format string has been removed.
* The -I option to show-messages has been removed.  See:

  #{t:start_time}

  format option instead.

Normal Changes
==============

* Panes are unzoomed with selectp -LRUD
* New formats added:

  #{scroll_position}
  #{socket_path}
  #{=10:...} -- limit to N characters (from the start)
  #{=-10:...} -- limit to N characters (from the end)
  #{t:...} -- used to format time-based formats
  #{b:...} -- used to ascertain basename from string
  #{d:...} -- used to ascertain dirname from string
  #{s:...} -- used to perform substitutions on a string

* Job output is run via the format system, so formats work again
* If display-time is set to 0, then the indicators wait for a key to be
  pressed.
* list-keys and list-commands can be run without starting the tmux server.
* kill-session learns -C to clear all alerts in all windows of the session.
* Support for hooks (internal for now), but hooks for the following have been
  implemented:

  alert-bell
  alert-silence
  alert-activity
  client-attached
  client-detached
  client-resized
  pane-died
  pane-exited

* RGB (24bit) colour support.  The 'Tc' flag must be set in the external TERM
  entry (using terminal-overrides or a custom terminfo entry).

CHANGES FROM 2.0 TO 2.1, 18 October 2015

Incompatible Changes
====================

* Mouse-mode has been rewritten.  There's now no longer options for:
	- mouse-resize-pane
	- mouse-select-pane
	- mouse-select-window
	- mode-mouse

  Instead there is just one option:  'mouse' which turns on mouse support
  entirely.
* 'default-terminal' is now a session option.  Furthermore, if this is set
  to 'screen-*' then emulate what screen does.  If italics are wanted, this
  can be set to 'tmux' but this is still new and not necessarily supported
  on all platforms with older ncurses installs.
* The c0-* options for rate-limiting have been removed.  Instead, a backoff
  approach is used.

Normal Changes
==============

* New formats:
	- session_activity
	- window_linked
	- window_activity_format
	- session_alerts
	- session_last_attached
	- client_pid
	- pid
* 'copy-selection', 'append-selection', 'start-named-buffer' now understand
  an '-x' flag to prevent it exiting copying mode.
* 'select-pane' now understands '-P' to set window/pane background colours.
* 'renumber-windows' now understands windows which are unlinked.
* 'bind' now understands multiple key tables.  Allows for key-chaining.
* 'select-layout' understands '-o' to undo the last layout change.
* The environment is updated when switching sessions as well as attaching.
* 'select-pane' now understands '-M' for marking a pane.  This marked pane
  can then be used with commands which understand src-pane specifiers
  automatically.
* If a session/window target is prefixed with '=' then only an exact match
  is considered.
* 'move-window' understands '-a'.
* 'update-environment' understands '-E' when attach-session is used on an
  already attached client.
* 'show-environment' understands '-s' to output Bourne-compatible commands.
* New option: 'history-file' to save/restore command prompt history.
* Copy mode is exited if the history is cleared whilst in copy-mode.
* 'copy-mode' learned '-e' to exit copy-mode when scrolling to end.

CHANGES FROM 1.9a TO 2.0, 06 March 2015

Incompatible Changes
====================

* The choose-list command has been removed.
* 'terminal-overrides' is now a server option, not a session option.
* 'message-limit' is now a server option, not a session option.
* 'monitor-content' option has been removed.
* 'pane_start_path' option has been removed.
* The "info" mechanism which used to (for some commands) provide feedback
  has been removed, and like other commands, they now produce nothing on
  success.

Normal Changes
==============

* tmux can now write an entry to utmp if the library 'utempter' is present
  at compile time.
* set-buffer learned append mode (-a), and a corresponding
  'append-selection' command has been added to copy-mode.
* choose-mode now has the following commands which can be bound:
	- start-of-list
	- end-of-list
	- top-line
	- bottom-line

* choose-buffer now understands UTF-8.
* Pane navigation has changed:
	- The old way of always using the top or left if the choice is ambiguous.
	- The new way of remembering the last used pane is annoying if the
	  layout is balanced and the leftmost is obvious to the user (because
	  clearly if we go right from the top-left in a tiled set of four we want
	  to end up in top-right, even if we were last using the bottom-right).

      So instead, use a combination of both: if there is only one possible
      pane alongside the current pane, move to it, otherwise choose the most
      recently used of the choice.
* 'set-buffer' can now be told to give names to buffers.
* The 'new-session', 'new-window', 'split-window', and 'respawn-pane' commands
  now understand multiple arguments and handle quoting problems correctly.
* 'capture-pane' understands '-S-' to mean the start of the pane, and '-E-' to
  mean the end of the pane.
* Support for function keys beyond F12 has changed.  The following explains:
	- F13-F24 are S-F1 to S-F12
	- F25-F36 are C-F1 to C-F12
	- F37-F48 are C-S-F1 to C-S-F12
	- F49-F60 are M-F1 to M-F12
	- F61-F63 are M-S-F1 to M-S-F3

 Therefore, F13 becomes a binding of S-F1, etc.
* Support using pane id as part of session or window specifier (so % means
  session-of-%1 or window-of-%1) and window id as part of session
  (so @1 means session-of-@1).
* 'copy-pipe' command now understands formats via -F
* 'if-shell'  command now understands formats via -F
* 'split-window' and 'join-window' understand -b to create the pane to the left
  or above the target pane.

CHANGES FROM 1.9 TO 1.9a, 22 February 2014

NOTE: This is a bug-fix release to address some important bugs which just
missed the 1.9 deadline, but were found afterwards.

Normal Changes
==============

* Fix crash due to uninitialized lastwp member of layout_cell
* Fix -fg/-bg/-style with 256 colour terminals.

CHANGES FROM 1.8 TO 1.9, 20 February 2014

NOTE:  This release has bumped the tmux protocol version.  It is therefore
