diff --git a/runtime/syntax/tmux.vim b/runtime/syntax/tmux.vim
index 867c033..042b96e 100644
--- a/runtime/syntax/tmux.vim
+++ b/runtime/syntax/tmux.vim
@@ -1,5 +1,5 @@
 " Language: tmux(1) configuration file
-" Version: 3.2a (git-44ada9cd)
+" Version: 3.3-rc (git-964deae4)
 " URL: https://github.com/ericpruitt/tmux.vim/
 " Maintainer: Eric Pruitt <eric.pruitt@gmail.com>
 " License: 2-Clause BSD (http://opensource.org/licenses/BSD-2-Clause)
@@ -18,40 +18,49 @@
 syntax case match
 
 syn keyword tmuxAction  none any current other
-syn keyword tmuxBoolean off on
+syn keyword tmuxBoolean off on yes no
 
 syn keyword tmuxTodo FIXME NOTE TODO XXX contained
 
-syn match tmuxColour            /\<colour[0-9]\+/      display
+syn match tmuxColour            /\<colou\?r[0-9]\+\>/  display
 syn match tmuxKey               /\(C-\|M-\|\^\)\+\S\+/ display
 syn match tmuxNumber            /\<\d\+\>/             display
 syn match tmuxFlags             /\s-\a\+/              display
-syn match tmuxVariable          /\w\+=/                display
-syn match tmuxVariableExpansion /\${\=\w\+}\=/         display
-syn match tmuxControl           /%\(if\|elif\|else\|endif\)/
+syn match tmuxVariableExpansion /\$\({[A-Za-z_]\w*}\|[A-Za-z_]\w*\)/ display
+syn match tmuxControl           /^\s*%\(if\|elif\|else\|endif\)\>/
+syn match tmuxEscape            /\\\(u\x\{4\}\|U\x\{8\}\|\o\{3\}\|[\\ernt$]\)/ display
 
 syn region tmuxComment start=/#/ skip=/\\\@<!\\$/ end=/$/ contains=tmuxTodo,@Spell
 
-syn region tmuxString start=+"+ skip=+\\\\\|\\"\|\\$+ excludenl end=+"+ end='$' contains=tmuxFormatString,@Spell
-syn region tmuxString start=+'+ skip=+\\\\\|\\'\|\\$+ excludenl end=+'+ end='$' contains=tmuxFormatString,@Spell
+syn region tmuxString start=+"+ skip=+\\\\\|\\"\|\\$+ excludenl end=+"+ end='$' contains=tmuxFormatString,tmuxEscape,tmuxVariableExpansion,@Spell
+syn region tmuxUninterpolatedString start=+'+ skip=+\\$+ excludenl end=+'+ end='$' contains=tmuxFormatString,@Spell
 
 " TODO: Figure out how escaping works inside of #(...) and #{...} blocks.
 syn region tmuxFormatString start=/#[#DFhHIPSTW]/ end=// contained keepend
 syn region tmuxFormatString start=/#{/ skip=/#{.\{-}}/ end=/}/ keepend
 syn region tmuxFormatString start=/#(/ skip=/#(.\{-})/ end=/)/ contained keepend
 
+" At the time of this writing, the latest tmux release will parse a line
+" reading "abc=xyz set-option ..." as an assignment followed by a command
+" hence the presence of "\s" in the "end" argument.
+syn region tmuxAssignment matchgroup=tmuxVariable start=/^\s*[A-Za-z_]\w*=\@=/ skip=/\\$\|\\\s/ end=/\s\|$/ contains=tmuxString,tmuxUninterpolatedString,tmuxVariableExpansion,tmuxControl,tmuxEscape
+
 hi def link tmuxFormatString      Identifier
 hi def link tmuxAction            Boolean
 hi def link tmuxBoolean           Boolean
 hi def link tmuxCommands          Keyword
-hi def link tmuxControl           Keyword
+hi def link tmuxControl           PreCondit
 hi def link tmuxComment           Comment
+hi def link tmuxEscape            Special
+hi def link tmuxEscapeUnquoted    Special
 hi def link tmuxKey               Special
 hi def link tmuxNumber            Number
 hi def link tmuxFlags             Identifier
 hi def link tmuxOptions           Function
 hi def link tmuxString            String
 hi def link tmuxTodo              Todo
+hi def link tmuxUninterpolatedString
+\                                 String
 hi def link tmuxVariable          Identifier
 hi def link tmuxVariableExpansion Identifier
 
@@ -61,63 +70,85 @@
 if get(g:, "tmux_syntax_colors", 1)
     for s:i in range(0, 255)
         let s:bg = (!s:i || s:i == 16 || (s:i > 231 && s:i < 235)) ? 15 : "none"
-        exec "syn match tmuxColour" . s:i . " /\\<colour" . s:i . "\\>/ display"
+        exec "syn match tmuxColour" . s:i . " /\\<colou\\?r" . s:i . "\\>/ display"
 \         " | highlight tmuxColour" . s:i . " ctermfg=" . s:i . " ctermbg=" . s:bg
     endfor
 endif
 
 syn keyword tmuxOptions
-\ backspace buffer-limit command-alias copy-command default-terminal editor
-\ escape-time exit-empty activity-action assume-paste-time base-index
-\ bell-action default-command default-shell default-size destroy-unattached
+\ activity-action after-bind-key after-capture-pane after-copy-mode
+\ after-display-message after-display-panes after-kill-pane
+\ after-list-buffers after-list-clients after-list-keys after-list-panes
+\ after-list-sessions after-list-windows after-load-buffer after-lock-server
+\ after-new-session after-new-window after-paste-buffer after-pipe-pane
+\ after-queue after-refresh-client after-rename-session after-rename-window
+\ after-resize-pane after-resize-window after-save-buffer
+\ after-select-layout after-select-pane after-select-window after-send-keys
+\ after-set-buffer after-set-environment after-set-hook after-set-option
+\ after-show-environment after-show-messages after-show-options
+\ after-split-window after-unbind-key aggressive-resize alert-activity
+\ alert-bell alert-silence allow-passthrough allow-rename alternate-screen
+\ assume-paste-time automatic-rename automatic-rename-format backspace
+\ base-index bell-action buffer-limit client-active client-attached
+\ client-detached client-focus-in client-focus-out client-resized
+\ client-session-changed clock-mode-colour clock-mode-style command-alias
+\ copy-command copy-mode-current-match-style copy-mode-mark-style
+\ copy-mode-match-style cursor-colour cursor-style default-command
+\ default-shell default-size default-terminal destroy-unattached
 \ detach-on-destroy display-panes-active-colour display-panes-colour
-\ display-panes-time display-time exit-unattached extended-keys focus-events
-\ history-file history-limit key-table lock-after-time lock-command
-\ message-command-style message-limit message-style aggressive-resize
-\ allow-rename alternate-screen automatic-rename automatic-rename-format
-\ clock-mode-colour clock-mode-style copy-mode-current-match-style
-\ copy-mode-mark-style copy-mode-match-style main-pane-height
-\ main-pane-width mode-keys mode-style monitor-activity monitor-bell
-\ monitor-silence mouse other-pane-height other-pane-width
-\ pane-active-border-style pane-base-index pane-border-format
-\ pane-border-lines pane-border-status pane-border-style pane-colours prefix
-\ prefix2 prompt-history-limit remain-on-exit renumber-windows repeat-time
-\ set-clipboard set-titles set-titles-string silence-action status status-bg
-\ status-fg status-format status-interval status-justify status-keys
-\ status-left status-left-length status-left-style status-position
-\ status-right status-right-length status-right-style status-style
-\ synchronize-panes terminal-features terminal-overrides update-environment
-\ user-keys visual-activity visual-bell visual-silence window-active-style
+\ display-panes-time display-time editor escape-time exit-empty
+\ exit-unattached extended-keys fill-character focus-events history-file
+\ history-limit key-table lock-after-time lock-command main-pane-height
+\ main-pane-width message-command-style message-limit message-style
+\ mode-keys mode-style monitor-activity monitor-bell monitor-silence mouse
+\ other-pane-height other-pane-width pane-active-border-style
+\ pane-base-index pane-border-format pane-border-indicators
+\ pane-border-lines pane-border-status pane-border-style pane-colours
+\ pane-died pane-exited pane-focus-in pane-focus-out pane-mode-changed
+\ pane-set-clipboard pane-title-changed popup-border-lines
+\ popup-border-style popup-style prefix prefix2 prompt-history-limit
+\ remain-on-exit remain-on-exit-format renumber-windows repeat-time
+\ scroll-on-clear session-closed session-created session-renamed
+\ session-window-changed set-clipboard set-titles set-titles-string
+\ silence-action status status-bg status-fg status-format status-interval
+\ status-justify status-keys status-left status-left-length
+\ status-left-style status-position status-right status-right-length
+\ status-right-style status-style synchronize-panes terminal-features
+\ terminal-overrides update-environment user-keys visual-activity
+\ visual-bell visual-silence window-active-style window-layout-changed
+\ window-linked window-pane-changed window-renamed window-resized
 \ window-size window-status-activity-style window-status-bell-style
 \ window-status-current-format window-status-current-style
 \ window-status-format window-status-last-style window-status-separator
-\ window-status-style window-style word-separators wrap-search
+\ window-status-style window-style window-unlinked word-separators
+\ wrap-search xterm-keys
 
 syn keyword tmuxCommands
 \ attach attach-session bind bind-key break-pane breakp capture-pane
-\ capturep choose-buffer choose-client choose-tree clear-history clearhist
+\ capturep choose-buffer choose-client choose-session choose-tree
+\ choose-window clear-history clear-prompt-history clearhist clearphist
 \ clock-mode command-prompt confirm confirm-before copy-mode customize-mode
-\ detach detach-client display display-menu display-message display-panes
-\ display-popup displayp find-window findw if if-shell join-pane joinp
-\ kill-pane kill-server kill-session kill-window killp has has-session killw
+\ delete-buffer deleteb detach detach-client display display-menu
+\ display-message display-panes display-popup displayp find-window findw has
+\ has-session if if-shell info join-pane joinp kill-pane kill-server
+\ kill-session kill-window killp killw last last-pane last-window lastp
 \ link-window linkw list-buffers list-clients list-commands list-keys
 \ list-panes list-sessions list-windows load-buffer loadb lock lock-client
-\ lock-server lock-session lockc last-pane lastp locks ls last last-window
-\ lsb delete-buffer deleteb lsc lscm lsk lsp lsw menu move-pane move-window
-\ clear-prompt-history clearphist movep movew new new-session new-window
-\ neww next next-layout next-window nextl paste-buffer pasteb pipe-pane
-\ pipep popup prev previous-layout previous-window prevl refresh
-\ refresh-client rename rename-session rename-window renamew resize-pane
-\ resize-window resizep resizew respawn-pane respawn-window respawnp
-\ respawnw rotate-window rotatew run run-shell save-buffer saveb
-\ select-layout select-pane select-window selectl selectp selectw send
-\ send-keys send-prefix set set-buffer set-environment set-hook set-option
+\ lock-server lock-session lockc locks ls lsb lsc lscm lsk lsp lsw menu
+\ move-pane move-window movep movew new new-session new-window neww next
+\ next-layout next-window nextl paste-buffer pasteb pipe-pane pipep popup
+\ prev previous-layout previous-window prevl refresh refresh-client rename
+\ rename-session rename-window renamew resize-pane resize-window resizep
+\ resizew respawn-pane respawn-window respawnp respawnw rotate-window
+\ rotatew run run-shell save-buffer saveb select-layout select-pane
+\ select-window selectl selectp selectw send send-keys send-prefix
+\ server-info set set-buffer set-environment set-hook set-option
 \ set-window-option setb setenv setw show show-buffer show-environment
 \ show-hooks show-messages show-options show-prompt-history
 \ show-window-options showb showenv showmsgs showphist showw source
-\ source-file split-window splitw start start-server suspend-client suspendc
-\ swap-pane swap-window swapp swapw switch-client switchc unbind unbind-key
-\ unlink-window unlinkw wait wait-for
+\ source-file split-pane split-window splitp splitw start start-server
+\ suspend-client suspendc swap-pane swap-window swapp swapw switch-client
+\ switchc unbind unbind-key unlink-window unlinkw wait wait-for
 
 let &cpo = s:original_cpo
 unlet! s:original_cpo s:bg s:i