diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5cb3772ef08..5514740c795 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,15 @@ This release no longer supports WERL (a graphical user interface for the Erlang
 
 ### 4. Hard deprecations
 
+#### EEx
+
+  * [EEx] `<%#` is deprecated in favor of `<%!--` or `<% #`
+  * [EEx] `c:EEx.handle_text/2` is deprecated in favor of `c:EEx.handle_text/3`
+
+#### Mix
+
+  * [mix cmd] Deprecate `mix cmd --app APP` in favor of `mix do --app APP`
+
 ## v1.17
 
 The CHANGELOG for v1.17 releases can be found [in the v1.17 branch](https://github.com/elixir-lang/elixir/blob/v1.17/CHANGELOG.md).
diff --git a/lib/eex/lib/eex/compiler.ex b/lib/eex/lib/eex/compiler.ex
index 63910400c6c..4f9f2f7ded9 100644
--- a/lib/eex/lib/eex/compiler.ex
+++ b/lib/eex/lib/eex/compiler.ex
@@ -48,8 +48,14 @@ defmodule EEx.Compiler do
     end
   end
 
-  # TODO: Deprecate this on Elixir v1.18
+  # TODO: Remove me on Elixir v2.0
   defp tokenize(~c"<%#" ++ t, line, column, state, buffer, acc) do
+    IO.warn("<%# is deprecated, use <%!-- or add a space between <% and # instead",
+      line: line,
+      column: column,
+      file: state.file
+    )
+
     case expr(t, line, column + 3, state, []) do
       {:error, message} ->
         {:error, message, %{line: line, column: column}}
@@ -299,6 +305,13 @@ defmodule EEx.Compiler do
     }
 
     init = state.engine.init(opts)
+
+    if function_exported?(state.engine, :handle_text, 2) do
+      IO.warn(
+        "#{inspect(state.engine)}.handle_text/2 is deprecated, implement handle_text/3 instead"
+      )
+    end
+
     generate_buffer(tokens, init, [], state)
   end
 
@@ -316,8 +329,7 @@ defmodule EEx.Compiler do
         meta = [line: meta.line, column: meta.column]
         state.engine.handle_text(buffer, meta, IO.chardata_to_string(chars))
       else
-        # TODO: Deprecate this branch on Elixir v1.18.
-        # We should most likely move this check to init to emit the deprecation once.
+        # TODO: Remove this on Elixir v2.0. The deprecation is on init.
         state.engine.handle_text(buffer, IO.chardata_to_string(chars))
       end
 
diff --git a/lib/eex/test/eex/tokenizer_test.exs b/lib/eex/test/eex/tokenizer_test.exs
index f452bfbcf2e..38cbca4e317 100644
--- a/lib/eex/test/eex/tokenizer_test.exs
+++ b/lib/eex/test/eex/tokenizer_test.exs
@@ -126,51 +126,21 @@ defmodule EEx.TokenizerTest do
   end
 
   test "EEx comments" do
-    exprs = [
-      {:text, ~c"foo ", %{column: 1, line: 1}},
-      {:eof, %{column: 16, line: 1}}
-    ]
+    ExUnit.CaptureIO.capture_io(:stderr, fn ->
+      exprs = [
+        {:text, ~c"foo ", %{column: 1, line: 1}},
+        {:eof, %{column: 16, line: 1}}
+      ]
 
-    assert EEx.tokenize(~c"foo <%# true %>", @opts) == {:ok, exprs}
+      assert EEx.tokenize(~c"foo <%# true %>", @opts) == {:ok, exprs}
 
-    exprs = [
-      {:text, ~c"foo ", %{column: 1, line: 1}},
-      {:eof, %{column: 8, line: 2}}
-    ]
+      exprs = [
+        {:text, ~c"foo ", %{column: 1, line: 1}},
+        {:eof, %{column: 8, line: 2}}
+      ]
 
-    assert EEx.tokenize(~c"foo <%#\ntrue %>", @opts) == {:ok, exprs}
-  end
-
-  test "EEx comments with do-end" do
-    exprs = [
-      {:text, ~c"foo ", %{column: 1, line: 1}},
-      {:text, ~c"bar", %{column: 19, line: 1}},
-      {:eof, %{column: 32, line: 1}}
-    ]
-
-    assert EEx.tokenize(~c"foo <%# true do %>bar<%# end %>", @opts) == {:ok, exprs}
-  end
-
-  test "EEx comments inside do-end" do
-    exprs = [
-      {:start_expr, ~c"", ~c" if true do ", %{column: 1, line: 1}},
-      {:text, ~c"bar", %{column: 31, line: 1}},
-      {:end_expr, [], ~c" end ", %{column: 34, line: 1}},
-      {:eof, %{column: 43, line: 1}}
-    ]
-
-    assert EEx.tokenize(~c"<% if true do %><%# comment %>bar<% end %>", @opts) == {:ok, exprs}
-
-    exprs = [
-      {:start_expr, [], ~c" case true do ", %{column: 1, line: 1}},
-      {:middle_expr, ~c"", ~c" true -> ", %{column: 33, line: 1}},
-      {:text, ~c"bar", %{column: 46, line: 1}},
-      {:end_expr, [], ~c" end ", %{column: 49, line: 1}},
-      {:eof, %{column: 58, line: 1}}
-    ]
-
-    assert EEx.tokenize(~c"<% case true do %><%# comment %><% true -> %>bar<% end %>", @opts) ==
-             {:ok, exprs}
+      assert EEx.tokenize(~c"foo <%#\ntrue %>", @opts) == {:ok, exprs}
+    end)
   end
 
   test "EEx multi-line comments" do
@@ -321,15 +291,6 @@ defmodule EEx.TokenizerTest do
     assert EEx.tokenize(template, [trim: true] ++ @opts) == {:ok, exprs}
   end
 
-  test "trim mode with comment" do
-    exprs = [
-      {:text, ~c"\n123", %{column: 19, line: 1}},
-      {:eof, %{column: 4, line: 2}}
-    ]
-
-    assert EEx.tokenize(~c"  <%# comment %>  \n123", [trim: true] ++ @opts) == {:ok, exprs}
-  end
-
   test "trim mode with multi-line comment" do
     exprs = [
       {:comment, ~c" comment ", %{column: 3, line: 1}},
@@ -384,9 +345,6 @@ defmodule EEx.TokenizerTest do
     assert EEx.tokenize(~c"foo <% :bar", @opts) ==
              {:error, message, %{column: 5, line: 1}}
 
-    assert EEx.tokenize(~c"<%# true ", @opts) ==
-             {:error, "expected closing '%>' for EEx expression", %{column: 1, line: 1}}
-
     message = """
     expected closing '--%>' for EEx expression
       |
diff --git a/lib/eex/test/eex_test.exs b/lib/eex/test/eex_test.exs
index 8436bd65b3b..b4621ca01a7 100644
--- a/lib/eex/test/eex_test.exs
+++ b/lib/eex/test/eex_test.exs
@@ -198,15 +198,6 @@ defmodule EExTest do
       assert_eval("foo baz", "foo <%= if false do %>bar<% else %>baz<% end %>")
     end
 
-    test "embedded code with comments in do end" do
-      assert_eval("foo bar", "foo <%= case true do %><%# comment %><% true -> %>bar<% end %>")
-
-      assert_eval(
-        "foo\n\nbar\n",
-        "foo\n<%= case true do %>\n<%# comment %>\n<% true -> %>\nbar\n<% end %>"
-      )
-    end
-
     test "embedded code with multi-line comments in do end" do
       assert_eval("foo bar", "foo <%= case true do %><%!-- comment --%><% true -> %>bar<% end %>")
 
diff --git a/lib/elixir/lib/code/formatter.ex b/lib/elixir/lib/code/formatter.ex
index fc8d8a9cd37..edee3ae9bb2 100644
--- a/lib/elixir/lib/code/formatter.ex
+++ b/lib/elixir/lib/code/formatter.ex
@@ -16,7 +16,7 @@ defmodule Code.Formatter do
   @ampersand_prec Code.Identifier.unary_op(:&) |> elem(1)
 
   # Operators that are composed of multiple binary operators
-  @multi_binary_operators [:"..//"]
+  @multi_binary_operators [:..//]
 
   # Operators that do not have space between operands
   @no_space_binary_operators [:.., :"//"]
@@ -492,7 +492,7 @@ defmodule Code.Formatter do
   end
 
   # 1..2//3
-  defp quoted_to_algebra({:"..//", meta, [left, middle, right]}, context, state) do
+  defp quoted_to_algebra({:..//, meta, [left, middle, right]}, context, state) do
     quoted_to_algebra({:"//", meta, [{:.., meta, [left, middle]}, right]}, context, state)
   end
 
@@ -524,10 +524,6 @@ defmodule Code.Formatter do
       if keyword_key?(left_arg) do
         {left, state} =
           case left_arg do
-            # TODO: Remove this clause in v1.18 when we no longer quote operator :..//
-            {:__block__, _, [:"..//"]} ->
-              {string(~S{"..//":}), state}
-
             {:__block__, _, [atom]} when is_atom(atom) ->
               iodata =
                 if Macro.classify_atom(atom) in [:identifier, :unquoted] do
@@ -1571,11 +1567,6 @@ defmodule Code.Formatter do
     Atom.to_string(nil) |> color(nil, inspect_opts)
   end
 
-  # TODO: Remove this clause in v1.18 when we no longer quote operator :..//
-  defp atom_to_algebra(:"..//", _, inspect_opts) do
-    string(":\"..//\"") |> color(:atom, inspect_opts)
-  end
-
   defp atom_to_algebra(:\\, meta, inspect_opts) do
     # Since we parse strings without unescaping, the atoms
     # :\\ and :"\\" have the same representation, so we need
diff --git a/lib/elixir/lib/code/normalizer.ex b/lib/elixir/lib/code/normalizer.ex
index f86ca831424..6b6dfe5e1c0 100644
--- a/lib/elixir/lib/code/normalizer.ex
+++ b/lib/elixir/lib/code/normalizer.ex
@@ -58,7 +58,7 @@ defmodule Code.Normalizer do
       {:.., meta, [left, right]}
     else
       step = do_normalize(step, state)
-      {:"..//", meta, [left, right, step]}
+      {:..//, meta, [left, right, step]}
     end
   end
 
diff --git a/lib/elixir/lib/exception.ex b/lib/elixir/lib/exception.ex
index 9641b405cd6..9389f7f2199 100644
--- a/lib/elixir/lib/exception.ex
+++ b/lib/elixir/lib/exception.ex
@@ -346,7 +346,7 @@ defmodule Exception do
   defp rewrite_arg(arg) do
     Macro.prewalk(arg, fn
       {:%{}, meta, [__struct__: Range, first: first, last: last, step: step]} ->
-        {:"..//", meta, [first, last, step]}
+        {:..//, meta, [first, last, step]}
 
       other ->
         other
diff --git a/lib/elixir/lib/macro.ex b/lib/elixir/lib/macro.ex
index e6ded3f4eb7..7839a7c006d 100644
--- a/lib/elixir/lib/macro.ex
+++ b/lib/elixir/lib/macro.ex
@@ -1484,7 +1484,7 @@ defmodule Macro do
     :error
   end
 
-  defp op_call({:"..//", _, [left, middle, right]} = ast, fun) do
+  defp op_call({:..//, _, [left, middle, right]} = ast, fun) do
     left = op_to_string(left, fun, :.., :left)
     middle = op_to_string(middle, fun, :.., :right)
     right = op_to_string(right, fun, :"//", :right)
@@ -1935,7 +1935,7 @@ defmodule Macro do
   @spec operator?(name :: atom(), arity()) :: boolean()
   def operator?(name, arity)
 
-  def operator?(:"..//", 3),
+  def operator?(:..//, 3),
     do: true
 
   # Code.Identifier treats :// as a binary operator for precedence
@@ -2454,7 +2454,7 @@ defmodule Macro do
   #
   defp inner_classify(atom) when is_atom(atom) do
     cond do
-      atom in [:%, :%{}, :{}, :<<>>, :..., :.., :., :"..//", :->] ->
+      atom in [:%, :%{}, :{}, :<<>>, :..., :.., :., :..//, :->] ->
         :not_callable
 
       # <|>, ^^^, and ~~~ are deprecated
diff --git a/lib/elixir/test/elixir/code_formatter/literals_test.exs b/lib/elixir/test/elixir/code_formatter/literals_test.exs
index 7f5a7632faf..99b3456bde5 100644
--- a/lib/elixir/test/elixir/code_formatter/literals_test.exs
+++ b/lib/elixir/test/elixir/code_formatter/literals_test.exs
@@ -112,10 +112,6 @@ defmodule Code.Formatter.LiteralsTest do
 
     test "quoted operators" do
       assert_same ~S[:"::"]
-      assert_same ~S[:"..//"]
-      assert_format ~S[:..//], ~S[:"..//"]
-      assert_format ~S{[..//: 1]}, ~S{["..//": 1]}
-      assert_same ~S{["..//": 1]}
     end
 
     test "uses double quotes even when single quotes are used" do
diff --git a/lib/elixir/test/elixir/kernel/parser_test.exs b/lib/elixir/test/elixir/kernel/parser_test.exs
index 6d5536c8938..72a1d615111 100644
--- a/lib/elixir/test/elixir/kernel/parser_test.exs
+++ b/lib/elixir/test/elixir/kernel/parser_test.exs
@@ -66,13 +66,13 @@ defmodule Kernel.ParserTest do
 
   describe "ternary ops" do
     test "root" do
-      assert parse!("1..2//3") == {:"..//", [line: 1], [1, 2, 3]}
-      assert parse!("(1..2)//3") == {:"..//", [line: 1], [1, 2, 3]}
+      assert parse!("1..2//3") == {:..//, [line: 1], [1, 2, 3]}
+      assert parse!("(1..2)//3") == {:..//, [line: 1], [1, 2, 3]}
     end
 
     test "with do-blocks" do
       assert parse!("foo do end..bar do end//baz do end") == {
-               :"..//",
+               :..//,
                [line: 1],
                [
                  {:foo, [line: 1], [[do: {:__block__, [], []}]]},
@@ -84,7 +84,7 @@ defmodule Kernel.ParserTest do
 
     test "with no parens" do
       assert parse!("1..foo do end//bar bat") == {
-               :"..//",
+               :..//,
                [line: 1],
                [
                  1,
diff --git a/lib/logger/lib/logger.ex b/lib/logger/lib/logger.ex
index a29c5b6628c..14ee9f6f9e8 100644
--- a/lib/logger/lib/logger.ex
+++ b/lib/logger/lib/logger.ex
@@ -564,7 +564,7 @@ defmodule Logger do
 
       delete_process_level(pid)
   """
-  # TODO: Deprecate me on v1.18
+  # TODO: Deprecate me on v1.19
   @doc deprecated: "Use Logger.delete_process_level(pid) instead"
   @spec enable(pid) :: :ok
   def enable(pid) when pid == self() do
@@ -580,7 +580,7 @@ defmodule Logger do
 
       put_process_level(pid, :none)
   """
-  # TODO: Deprecate me on v1.18
+  # TODO: Deprecate me on v1.20
   @doc deprecated: "Use Logger.put_process_level(pid, :none) instead"
   @spec disable(pid) :: :ok
   def disable(pid) when pid == self() do
@@ -592,7 +592,7 @@ defmodule Logger do
 
   Currently the only accepted PID is `self()`.
   """
-  # TODO: Deprecate me on v1.18
+  # TODO: Deprecate me on v1.20
   @doc deprecated: "Use Logger.get_process_level(pid) instead"
   @spec enabled?(pid) :: boolean
   def enabled?(pid) when pid == self() do
@@ -828,7 +828,7 @@ defmodule Logger do
   @doc """
   Adds a new backend.
   """
-  # TODO: Deprecate this on Elixir v1.19
+  # TODO: Deprecate this on Elixir v1.20
   @doc deprecated: "Use LoggerBackends.add/2 from :logger_backends dependency"
   def add_backend(backend, opts \\ []) do
     Logger.Backends.Internal.add(backend, opts)
@@ -837,7 +837,7 @@ defmodule Logger do
   @doc """
   Removes a backend.
   """
-  # TODO: Deprecate this on Elixir v1.19
+  # TODO: Deprecate this on Elixir v1.20
   @doc deprecated: "Use LoggerBackends.remove/2 from :logger_backends dependency"
   def remove_backend(backend, opts \\ []) do
     Logger.Backends.Internal.remove(backend, opts)
@@ -846,7 +846,7 @@ defmodule Logger do
   @doc """
   Configures the given backend.
   """
-  # TODO: Deprecate this on Elixir v1.19
+  # TODO: Deprecate this on Elixir v1.20
   @doc deprecated: "Use LoggerBackends.configure/2 from :logger_backends dependency"
   def configure_backend(:console, options) when is_list(options) do
     options = Keyword.merge(Application.get_env(:logger, :console, []), options)
diff --git a/lib/mix/lib/mix/tasks/cmd.ex b/lib/mix/lib/mix/tasks/cmd.ex
index 63cb96fcb4a..cfe43466db2 100644
--- a/lib/mix/lib/mix/tasks/cmd.ex
+++ b/lib/mix/lib/mix/tasks/cmd.ex
@@ -33,9 +33,6 @@ defmodule Mix.Tasks.Cmd do
 
   ## Command line options
 
-    * `--app` - limit running the command to the given app.
-      This option is currently deprecated in favor of `mix do --app`
-
     * `--cd` *(since v1.10.4)* - the directory to run the command in
 
   ## Zombie operating system processes
@@ -60,12 +57,15 @@ defmodule Mix.Tasks.Cmd do
   def run(args) do
     {opts, args} = OptionParser.parse_head!(args, strict: @switches)
 
-    # TODO: Deprecate `--app` flag in Elixir v1.18
     apps =
       opts
       |> Keyword.get_values(:app)
       |> Enum.map(&String.to_atom/1)
 
+    if apps != [] do
+      IO.warn("the --app in mix cmd is deprecated")
+    end
+
     if apps == [] or Mix.Project.config()[:app] in apps do
       cmd_opts = Keyword.take(opts, [:cd])
 
diff --git a/lib/mix/lib/mix/tasks/do.ex b/lib/mix/lib/mix/tasks/do.ex
index 924b99d8f81..c68fcb1c236 100644
--- a/lib/mix/lib/mix/tasks/do.ex
+++ b/lib/mix/lib/mix/tasks/do.ex
@@ -49,7 +49,7 @@ defmodule Mix.Tasks.Do do
 
   """
 
-  # TODO: Deprecate using comma on Elixir v1.18
+  # TODO: Deprecate using comma on Elixir v1.19
 
   @impl true
   def run(args) do
diff --git a/lib/mix/test/mix/tasks/cmd_test.exs b/lib/mix/test/mix/tasks/cmd_test.exs
index ac5360e818a..be437998539 100644
--- a/lib/mix/test/mix/tasks/cmd_test.exs
+++ b/lib/mix/test/mix/tasks/cmd_test.exs
@@ -25,39 +25,45 @@ defmodule Mix.Tasks.CmdTest do
   end
 
   test "runs the command for a single app specified by app flag" do
-    in_fixture("umbrella_dep/deps/umbrella", fn ->
-      Mix.Project.in_project(:umbrella, ".", fn _ ->
-        Mix.Task.run("cmd", ["--app", "bar", "echo", "hello"])
-        nl = os_newline()
-        assert_received {:mix_shell, :info, ["==> bar"]}
-        assert_received {:mix_shell, :run, ["hello" <> ^nl]}
-        refute_received {:mix_shell, :info, ["==> foo"]}
-        refute_received {:mix_shell, :run, ["hello" <> ^nl]}
+    ExUnit.CaptureIO.capture_io(:stderr, fn ->
+      in_fixture("umbrella_dep/deps/umbrella", fn ->
+        Mix.Project.in_project(:umbrella, ".", fn _ ->
+          Mix.Task.run("cmd", ["--app", "bar", "echo", "hello"])
+          nl = os_newline()
+          assert_received {:mix_shell, :info, ["==> bar"]}
+          assert_received {:mix_shell, :run, ["hello" <> ^nl]}
+          refute_received {:mix_shell, :info, ["==> foo"]}
+          refute_received {:mix_shell, :run, ["hello" <> ^nl]}
+        end)
       end)
     end)
   end
 
   test "runs the command for each app specified by app flag" do
-    in_fixture("umbrella_dep/deps/umbrella", fn ->
-      Mix.Project.in_project(:umbrella, ".", fn _ ->
-        Mix.Task.run("cmd", ["--app", "bar", "--app", "foo", "echo", "hello"])
-        nl = os_newline()
-        assert_received {:mix_shell, :info, ["==> bar"]}
-        assert_received {:mix_shell, :run, ["hello" <> ^nl]}
-        assert_received {:mix_shell, :info, ["==> foo"]}
-        assert_received {:mix_shell, :run, ["hello" <> ^nl]}
+    ExUnit.CaptureIO.capture_io(:stderr, fn ->
+      in_fixture("umbrella_dep/deps/umbrella", fn ->
+        Mix.Project.in_project(:umbrella, ".", fn _ ->
+          Mix.Task.run("cmd", ["--app", "bar", "--app", "foo", "echo", "hello"])
+          nl = os_newline()
+          assert_received {:mix_shell, :info, ["==> bar"]}
+          assert_received {:mix_shell, :run, ["hello" <> ^nl]}
+          assert_received {:mix_shell, :info, ["==> foo"]}
+          assert_received {:mix_shell, :run, ["hello" <> ^nl]}
+        end)
       end)
     end)
   end
 
   test "only runs the cmd for specified apps and in specific directory" do
-    in_fixture("umbrella_dep/deps/umbrella", fn ->
-      Mix.Project.in_project(:umbrella, ".", fn _ ->
-        Mix.Task.run("cmd", ["--app", "bar", "--cd", "lib", "pwd"])
-        assert_received {:mix_shell, :info, ["==> bar"]}
-        {pwd, 0} = System.cmd("pwd", [], cd: Path.join(["apps", "bar", "lib"]))
-        assert_received {:mix_shell, :run, [^pwd]}
-        refute_received {:mix_shell, :info, ["==> foo"]}
+    ExUnit.CaptureIO.capture_io(:stderr, fn ->
+      in_fixture("umbrella_dep/deps/umbrella", fn ->
+        Mix.Project.in_project(:umbrella, ".", fn _ ->
+          Mix.Task.run("cmd", ["--app", "bar", "--cd", "lib", "pwd"])
+          assert_received {:mix_shell, :info, ["==> bar"]}
+          {pwd, 0} = System.cmd("pwd", [], cd: Path.join(["apps", "bar", "lib"]))
+          assert_received {:mix_shell, :run, [^pwd]}
+          refute_received {:mix_shell, :info, ["==> foo"]}
+        end)
       end)
     end)
   end