diff --git a/core/core-modules.el b/core/core-modules.el
index 97e886ecb..0e8db1500 100644
--- a/core/core-modules.el
+++ b/core/core-modules.el
@@ -414,56 +414,5 @@ omitted. eg. (featurep! +flag1)"
                 (memq category (doom-module-get (car module-pair) (cdr module-pair) :flags)))))
        t))
 
-
-;;
-;; FIXME Cross-module configuration (deprecated)
-
-;; I needed a way to reliably cross-configure modules without littering my
-;; modules with `after!' blocks or testing whether they were enabled, so I wrote
-;; `set!'. If a setting doesn't exist at runtime, the `set!' call is ignored and
-;; its arguments are left unevaluated (and entirely omitted when byte-compiled).
-
-(defmacro def-setting! (keyword arglist &optional docstring &rest forms)
-  "Define a setting. Like `defmacro', this should return a form to be executed
-when called with `set!'. FORMS are not evaluated until `set!' calls it.
-
-See `doom/describe-setting' for a list of available settings.
-
-Do not use this for configuring Doom core."
-  (declare (indent defun) (doc-string 3))
-  (or (keywordp keyword)
-      (signal 'wrong-type-argument (list 'keywordp keyword)))
-  (unless (stringp docstring)
-    (push docstring forms)
-    (setq docstring nil))
-  (let ((alias (plist-get forms :obsolete)))
-    (when alias
-      (setq forms (plist-put forms :obsolete 'nil)))
-    `(fset ',(intern (format "doom--set%s" keyword))
-           (lambda ,arglist
-             ,(if (and (not docstring) (fboundp alias))
-                  (documentation alias t)
-                docstring)
-             ,(when alias
-                `(declare (obsolete ,alias "2.1.0")))
-             (prog1 (progn ,@forms)
-               ,(when alias
-                  `(unless noninteractive
-                     (message ,(format "The `%s' setting is deprecated, use `%s' instead"
-                                       keyword alias)))))))))
-
-(defmacro set! (keyword &rest values)
-  "Set an option defined by `def-setting!'. Skip if doesn't exist. See
-`doom/describe-setting' for a list of available settings.
-
-VALUES doesn't get evaluated if the KEYWORD setting doesn't exist."
-  (declare (indent defun))
-  (let ((fn (intern-soft (format "doom--set%s" keyword))))
-    (if (and fn (fboundp fn))
-        (apply fn values)
-      (when (or doom-debug-mode after-init-time)
-        (message "No setting found for %s" keyword)
-        nil))))
-
 (provide 'core-modules)
 ;;; core-modules.el ends here
diff --git a/core/core-os.el b/core/core-os.el
index 4ca91a5d8..cdaced36c 100644
--- a/core/core-os.el
+++ b/core/core-os.el
@@ -14,12 +14,6 @@
 (defmacro set-env! (&rest _vars)
   "Inject VARS from your shell environment into Emacs.")
 
-;; FIXME obsolete :env
-(def-setting! :env (&rest vars)
-  :obsolete set-env!
-  (when (featurep 'exec-path-from-shell)
-    `(exec-path-from-shell-copy-envs ,@vars)))
-
 (cond (IS-MAC
        (setq mac-command-modifier 'meta
              mac-option-modifier  'alt
diff --git a/modules/app/email/autoload/email.el b/modules/app/email/autoload/email.el
index a471fa181..5a468abc5 100644
--- a/modules/app/email/autoload/email.el
+++ b/modules/app/email/autoload/email.el
@@ -40,12 +40,6 @@ default/fallback account."
         (setq-default mu4e-context-current context))
       context)))
 
-;; FIXME obsolete :email
-;;;###autoload
-(def-setting! :email (label letvars &optional default-p)
-  :obsolete set-email-account!
-  `(set-email-acount! ,label ,letvars ,default-p))
-
 
 
 (defvar +email-workspace-name "*mu4e*"
diff --git a/modules/app/irc/autoload/settings.el b/modules/app/irc/autoload/settings.el
index 424a731cd..59615a760 100644
--- a/modules/app/irc/autoload/settings.el
+++ b/modules/app/irc/autoload/settings.el
@@ -7,10 +7,3 @@
 See `circe-network-options' for details."
   (after! circe
     (push (cons server letvars) circe-network-options)))
-
-;; FIXME obsolete :irc
-;;;###autoload
-(def-setting! :irc (server letvars)
-  :obsolete set-irc-server!
-  `(after! circe
-     (push (cons ,server ,letvars) circe-network-options)))
diff --git a/modules/completion/company/autoload.el b/modules/completion/company/autoload.el
index 5dfcf0bd7..1d4c4a784 100644
--- a/modules/completion/company/autoload.el
+++ b/modules/completion/company/autoload.el
@@ -47,12 +47,6 @@ To have BACKENDS apply to any mode that is a parent of MODES, set MODES to
         (setf (alist-get mode +company-backend-alist)
               (cons type backends))))))
 
-;; FIXME obsolete :company-backend
-;;;###autoload
-(def-setting! :company-backend (modes &rest backends)
-  :obsolete set-company-backend!
-  `(set-company-backend! ,modes ,@backends))
-
 
 ;;
 ;; Library
diff --git a/modules/editor/rotate-text/autoload.el b/modules/editor/rotate-text/autoload.el
index d5247e656..f696ead51 100644
--- a/modules/editor/rotate-text/autoload.el
+++ b/modules/editor/rotate-text/autoload.el
@@ -17,9 +17,3 @@
               (setq-local rotate-text-local-words words)
               (setq-local rotate-text-local-patterns patterns)))
       (add-hook (intern (format "%s-hook" mode)) fn-name))))
-
-;; FIXME obsolete :rotate
-;;;###autoload
-(def-setting! :rotate (modes &rest plist)
-  :obsolete set-rotate-patterns!
-  `(set-rotate-patterns! ,modes ,@plist))
diff --git a/modules/emacs/electric/autoload.el b/modules/emacs/electric/autoload.el
index 0b18f8d6e..3dbe4ec2f 100644
--- a/modules/emacs/electric/autoload.el
+++ b/modules/emacs/electric/autoload.el
@@ -22,9 +22,3 @@ Enables `electric-indent-local-mode' in MODES.
                        (if chars (setq electric-indent-chars chars))
                        (if words (setq +electric-indent-words words)))))
              (add-hook hook fn))))))
-
-;; FIXME obsolete :electric
-;;;###autoload
-(def-setting! :electric (modes &rest plist)
-  :obsolete set-electric!
-  `(set-electric! ,modes ,@plist))
diff --git a/modules/feature/eval/autoload/settings.el b/modules/feature/eval/autoload/settings.el
index b80af5d1a..d6fb3249f 100644
--- a/modules/feature/eval/autoload/settings.el
+++ b/modules/feature/eval/autoload/settings.el
@@ -20,12 +20,6 @@ command that will be called interactively."
   (dolist (mode (doom-enlist modes))
     (setf (alist-get mode +eval-repls) command)))
 
-;; FIXME obsolete :repl
-;;;###autoload
-(def-setting! :repl (mode command)
-  :obsolete set-repl-handler!
-  `(set-repl-handler! ,mode ,command))
-
 
 ;;
 ;; Evaluation
@@ -62,9 +56,3 @@ command that will be called interactively."
              (or (cdr (assq mode quickrun--major-mode-alist))
                  (string-remove-suffix "-mode" (symbol-name mode)))
              command :mode mode)))))
-
-;; FIXME obsolete :eval
-;;;###autoload
-(def-setting! :eval (mode command)
-  :obsolete set-eval-handler!
-  `(set-eval-handler! ,mode ,command))
diff --git a/modules/feature/evil/autoload/evil.el b/modules/feature/evil/autoload/evil.el
index 37988b8b2..1da151300 100644
--- a/modules/feature/evil/autoload/evil.el
+++ b/modules/feature/evil/autoload/evil.el
@@ -11,12 +11,6 @@
           (evil-set-initial-state mode state))
       (evil-set-initial-state modes state))))
 
-;; FIXME obsolete :evil-state
-;;;###autoload
-(def-setting! :evil-state (modes state)
-  :obsolete set-evil-initial-state!
-  `(set-evil-initial-state! ,modes ,state))
-
 
 ;;
 ;; Commands
diff --git a/modules/feature/file-templates/autoload.el b/modules/feature/file-templates/autoload.el
index 1d18419e6..4bcd8a1ad 100644
--- a/modules/feature/file-templates/autoload.el
+++ b/modules/feature/file-templates/autoload.el
@@ -48,18 +48,6 @@ these properties:
     (dolist (template templates)
       (+file-templates--set (car template) (cdr template)))))
 
-;; FIXME obsolete :file-template
-;;;###autoload
-(def-setting! :file-template (pred &rest plist)
-  :obsolete set-file-template!
-  `(set-file-template! ,pred ,@plist))
-
-;; FIXME obsolete :file-templates
-;;;###autoload
-(def-setting! :file-templates (&rest templates)
-  :obsolete set-file-templates!
-  `(set-file-templates! ,@templates))
-
 
 ;;
 ;; Library
diff --git a/modules/feature/lookup/autoload/docsets.el b/modules/feature/lookup/autoload/docsets.el
index d6e24a31b..405541211 100644
--- a/modules/feature/lookup/autoload/docsets.el
+++ b/modules/feature/lookup/autoload/docsets.el
@@ -43,12 +43,6 @@ Used by `+lookup/in-docsets' and `+lookup/documentation'."
                 (:remove (cl-set-difference (alist-get mode +lookup-docset-alist) docsets))
                 (_ docsets)))))))
 
-;; FIXME obsolete :docset
-;;;###autoload
-(def-setting! :docset (modes &rest docsets)
-  :obsolete set-docset!
-  `(set-docsets! ,modes ,@docsets))
-
 
 ;;
 ;; Library
diff --git a/modules/feature/lookup/autoload/lookup.el b/modules/feature/lookup/autoload/lookup.el
index dd89fa4dd..8f115a4a4 100644
--- a/modules/feature/lookup/autoload/lookup.el
+++ b/modules/feature/lookup/autoload/lookup.el
@@ -60,12 +60,6 @@ Otherwise, these properties are available to be set:
                            (add-hook 'xref-backend-functions xref-backend nil t))))))
              (add-hook hook fn))))))
 
-;; FIXME obsolete :lookup
-;;;###autoload
-(def-setting! :lookup (modes &rest plist)
-  :obsolete set-lookup-handlers!
-  `(set-lookup-handlers! ,modes ,@plist))
-
 
 ;;
 ;; Library
diff --git a/modules/feature/snippets/autoload/settings.el b/modules/feature/snippets/autoload/settings.el
index adb9f36da..6bb99df22 100644
--- a/modules/feature/snippets/autoload/settings.el
+++ b/modules/feature/snippets/autoload/settings.el
@@ -8,9 +8,3 @@ can have its own snippets category, if the folder exists."
     (let ((fn (intern (format "+snippets|register-%s" mode))))
       (fset fn (lambda () (yas-activate-extra-mode mode)))
       (add-hook (intern (format "%s-hook" mode)) fn))))
-
-;; FIXME obsolete :yas-minor-mode
-;;;###autoload
-(def-setting! :yas-minor-mode (mode)
-  :obsolete set-yas-minor-mode!
-  `(set-yas-minor-mode! ,mode))
diff --git a/modules/lang/emacs-lisp/autoload.el b/modules/lang/emacs-lisp/autoload.el
index 31800f138..482ace7c7 100644
--- a/modules/lang/emacs-lisp/autoload.el
+++ b/modules/lang/emacs-lisp/autoload.el
@@ -100,7 +100,6 @@ library/userland functions"
         '(("Evil Commands" "^\\s-*(evil-define-\\(?:command\\|operator\\|motion\\) +\\(\\_<[^ ()\n]+\\_>\\)" 1)
           ("Unit tests" "^\\s-*(\\(?:ert-deftest\\|describe\\) +\"\\([^\")]+\\)\"" 1)
           ("Package" "^\\s-*(\\(?:def-\\)?package! +\\(\\_<[^ ()\n]+\\_>\\)" 1)
-          ("Settings" "^\\s-*(def-setting! +\\([^ ()\n]+\\)" 1)
           ("Major modes" "^\\s-*(define-derived-mode +\\([^ ()\n]+\\)" 1)
           ("Modelines" "^\\s-*(def-modeline! +\\([^ ()\n]+\\)" 1)
           ("Modeline Segments" "^\\s-*(def-modeline-segment! +\\([^ ()\n]+\\)" 1)
diff --git a/modules/tools/ein/autoload.el b/modules/tools/ein/autoload.el
index 5ddcbaae5..9d35fb093 100644
--- a/modules/tools/ein/autoload.el
+++ b/modules/tools/ein/autoload.el
@@ -1,15 +1,5 @@
 ;;; tools/ein/autoload.el -*- lexical-binding: t; -*-
 
-;; FIXME obsolete :ein-notebook-dir
-;;;###autoload
-(def-setting! :ein-notebook-dir (dir)
-  "Set the default directory from where to open Jupyter notebooks."
-  `(setq ein:jupyter-default-notebook-directory ,dir))
-
-
-;;
-;; Library
-
 (defun +ein--collect-ein-buffer-links ()
   (let ((end (window-end))
         points)
diff --git a/modules/tools/prodigy/autoload.el b/modules/tools/prodigy/autoload.el
index d33a3d79e..0c013df59 100644
--- a/modules/tools/prodigy/autoload.el
+++ b/modules/tools/prodigy/autoload.el
@@ -1,12 +1,5 @@
 ;;; tools/prodigy/autoload.el -*- lexical-binding: t; -*-
 
-;; FIXME obsolete :service
-;;;###autoload
-(def-setting! :service (&rest plist)
-  "TODO"
-  `(after! prodigy
-     (prodigy-define-service ,@plist)))
-
 ;;;###autoload
 (defun +prodigy/create ()
   "Interactively create a new prodigy service."
diff --git a/modules/ui/popup/autoload/settings.el b/modules/ui/popup/autoload/settings.el
index 0148adda2..56a092f61 100644
--- a/modules/ui/popup/autoload/settings.el
+++ b/modules/ui/popup/autoload/settings.el
@@ -196,19 +196,3 @@ Example:
   (when (bound-and-true-p +popup-mode)
     (setq display-buffer-alist +popup--display-buffer-alist))
   +popup--display-buffer-alist)
-
-
-;;
-;; Obsolete settings
-
-;; FIXME obsolete :popup
-;;;###autoload
-(def-setting! :popup (condition &optional alist parameters)
-  :obsolete set-popup-rule!
-  `(set-popup-rule! ,condition ,alist ,parameters))
-
-;; FIXME obsolete :popups
-;;;###autoload
-(def-setting! :popups (&rest rulesets)
-  :obsolete set-popup-rules!
-  `(set-popup-rules! ,@rulesets))