diff --git a/autoload/ale/engine.vim b/autoload/ale/engine.vim
index 340f691304..6b312b4f4f 100644
--- a/autoload/ale/engine.vim
+++ b/autoload/ale/engine.vim
@@ -107,24 +107,36 @@ endfunction
 " Register a temporary file to be managed with the ALE engine for
 " a current job run.
 function! ale#engine#ManageFile(buffer, filename) abort
-    " TODO: Emit deprecation warning here later.
+    if !get(g:, 'ale_ignore_2_4_warnings')
+        execute 'echom ''ale#engine#ManageFile is deprecated. Use `let g:ale_ignore_2_4_warnings = 1` to disable this message.'''
+    endif
+
     call ale#command#ManageFile(a:buffer, a:filename)
 endfunction
 
 " Same as the above, but manage an entire directory.
 function! ale#engine#ManageDirectory(buffer, directory) abort
-    " TODO: Emit deprecation warning here later.
+    if !get(g:, 'ale_ignore_2_4_warnings')
+        execute 'echom ''ale#engine#ManageDirectory is deprecated. Use `let g:ale_ignore_2_4_warnings = 1` to disable this message.'''
+    endif
+
     call ale#command#ManageDirectory(a:buffer, a:directory)
 endfunction
 
 function! ale#engine#CreateFile(buffer) abort
-    " TODO: Emit deprecation warning here later.
+    if !get(g:, 'ale_ignore_2_4_warnings')
+        execute 'echom ''ale#engine#CreateFile is deprecated. Use `let g:ale_ignore_2_4_warnings = 1` to disable this message.'''
+    endif
+
     return ale#command#CreateFile(a:buffer)
 endfunction
 
 " Create a new temporary directory and manage it in one go.
 function! ale#engine#CreateDirectory(buffer) abort
-    " TODO: Emit deprecation warning here later.
+    if !get(g:, 'ale_ignore_2_4_warnings')
+        execute 'echom ''ale#engine#CreateDirectory is deprecated. Use `let g:ale_ignore_2_4_warnings = 1` to disable this message.'''
+    endif
+
     return ale#command#CreateDirectory(a:buffer)
 endfunction
 
diff --git a/autoload/ale/fix.vim b/autoload/ale/fix.vim
index b867460636..c0f05611a4 100644
--- a/autoload/ale/fix.vim
+++ b/autoload/ale/fix.vim
@@ -117,6 +117,10 @@ function! s:HandleExit(job_info, buffer, job_output, data) abort
         let l:input = a:job_info.input
     endif
 
+    if l:ChainCallback isnot v:null && !get(g:, 'ale_ignore_2_4_warnings')
+        execute 'echom ''chain_with is deprecated. Use `let g:ale_ignore_2_4_warnings = 1` to disable this message.'''
+    endif
+
     let l:next_index = l:ChainCallback is v:null
     \   ? a:job_info.callback_index + 1
     \   : a:job_info.callback_index
diff --git a/autoload/ale/linter.vim b/autoload/ale/linter.vim
index d680391d2f..273778c75f 100644
--- a/autoload/ale/linter.vim
+++ b/autoload/ale/linter.vim
@@ -340,7 +340,13 @@ function! ale#linter#PreProcess(filetype, linter) abort
         throw '`aliases` must be a List of String values'
     endif
 
-    " TODO: Emit deprecation warnings for deprecated options later.
+    for l:key in filter(keys(l:obj), 'v:val[-9:] is# ''_callback'' || v:val is# ''command_chain''')
+        if !get(g:, 'ale_ignore_2_4_warnings')
+            execute 'echom l:key . '' is deprecated. Use `let g:ale_ignore_2_4_warnings = 1` to disable this message.'''
+        endif
+
+        break
+    endfor
 
     return l:obj
 endfunction
diff --git a/test/lsp/test_reset_lsp.vader b/test/lsp/test_reset_lsp.vader
index 4a1a155e32..310b3d6291 100644
--- a/test/lsp/test_reset_lsp.vader
+++ b/test/lsp/test_reset_lsp.vader
@@ -25,10 +25,10 @@ Before:
   call ale#linter#Define('testft', {
   \   'name': 'lsplinter',
   \   'lsp': 'tsserver',
-  \   'executable_callback': 'EmptyString',
-  \   'command_callback': 'EmptyString',
-  \   'project_root_callback': 'EmptyString',
-  \   'language_callback': 'EmptyString',
+  \   'executable': function('EmptyString'),
+  \   'command': function('EmptyString'),
+  \   'project_root': function('EmptyString'),
+  \   'language': function('EmptyString'),
   \})
 
   call ale#linter#Define('testft', {
diff --git a/test/vimrc b/test/vimrc
index 9548f86175..018b8f67c1 100644
--- a/test/vimrc
+++ b/test/vimrc
@@ -35,3 +35,5 @@ set ttimeoutlen=0
 execute 'set encoding=utf-8'
 
 let g:mapleader=','
+
+let g:ale_ignore_2_4_warnings = 1