diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index a50544c..4f68530 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -15,19 +15,20 @@ jobs:
     name: Test (OTP ${{ matrix.otp }} / Elixir ${{ matrix.elixir }})
     strategy:
       matrix:
-        elixir: ["1.18", "1.17", "1.16", "1.15", "1.14"]
-        otp: ["27", "26", "25", "24"]
+        elixir: ["1.19", "1.18", "1.17", "1.16", "1.15"]
+        otp: ["28", "27", "26", "25", "24"]
         exclude:
-          - { otp: "25", elixir: "1.18" }
+          - { otp: "24", elixir: "1.19" }
           - { otp: "24", elixir: "1.18" }
           - { otp: "24", elixir: "1.17" }
+          - { otp: "25", elixir: "1.19" }
           - { otp: "27", elixir: "1.16" }
-          - { otp: "22", elixir: "1.16" }
           - { otp: "27", elixir: "1.15" }
-          - { otp: "27", elixir: "1.14" }
-          - { otp: "26", elixir: "1.14" }
+          - { otp: "28", elixir: "1.17" }
+          - { otp: "28", elixir: "1.16" }
+          - { otp: "28", elixir: "1.15" }
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: erlef/setup-beam@v1
         with:
           otp-version: ${{ matrix.otp }}
@@ -38,19 +39,15 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     name: Linting
-    strategy:
-      matrix:
-        elixir: ["1.18"]
-        otp: ["27"]
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: erlef/setup-beam@v1
         id: beam
         with:
-          otp-version: ${{ matrix.otp }}
-          elixir-version: ${{ matrix.elixir }}
+          version-file: .tool-versions
+          version-type: strict
       - name: PLT cache
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           key: |
             ${{ runner.os }}-${{ steps.beam.outputs.elixir-version }}-${{ steps.beam.outputs.otp-version }}-plt
diff --git a/.tool-versions b/.tool-versions
new file mode 100644
index 0000000..cdd7ae1
--- /dev/null
+++ b/.tool-versions
@@ -0,0 +1,2 @@
+erlang 28.3
+elixir 1.19.4-otp-28
diff --git a/lib/bgp/message/open.ex b/lib/bgp/message/open.ex
index 525b444..8e822a8 100644
--- a/lib/bgp/message/open.ex
+++ b/lib/bgp/message/open.ex
@@ -32,7 +32,7 @@ defmodule BGP.Message.OPEN do
   def decode(
         <<version::8, asn::16, hold_time::16, bgp_id::binary-size(4), _non_ext_params_length::8,
           255::8, length::16, params::binary-size(length)>>,
-        session
+        %Session{} = session
       ) do
     decode_open(
       version,
@@ -40,7 +40,7 @@ defmodule BGP.Message.OPEN do
       hold_time,
       bgp_id,
       params,
-      %Session{session | extended_optional_parameters: true}
+      %{session | extended_optional_parameters: true}
     )
   end
 
@@ -103,20 +103,20 @@ defmodule BGP.Message.OPEN do
 
   defp decode_parameters(
          <<2::8, length::16, parameter::binary-size(length), rest::binary>>,
-         msg,
+         %__MODULE__{} = msg,
          %Session{extended_optional_parameters: true} = session
        ) do
     {capabilities, session} = Capabilities.decode(parameter, session)
-    decode_parameters(rest, %__MODULE__{msg | capabilities: capabilities}, session)
+    decode_parameters(rest, %{msg | capabilities: capabilities}, session)
   end
 
   defp decode_parameters(
          <<2::8, length::8, parameter::binary-size(length), rest::binary>>,
-         msg,
+         %__MODULE__{} = msg,
          session
        ) do
     {capabilities, session} = Capabilities.decode(parameter, session)
-    decode_parameters(rest, %__MODULE__{msg | capabilities: capabilities}, session)
+    decode_parameters(rest, %{msg | capabilities: capabilities}, session)
   end
 
   @impl Encoder
diff --git a/lib/bgp/message/open/capabilities.ex b/lib/bgp/message/open/capabilities.ex
index 8ca2661..f95ab2b 100644
--- a/lib/bgp/message/open/capabilities.ex
+++ b/lib/bgp/message/open/capabilities.ex
@@ -47,35 +47,40 @@ defmodule BGP.Message.OPEN.Capabilities do
     decode_capabilities(rest, capabilities, session)
   end
 
-  defp decode_capability(1, <<afi::16, _reserved::8, safi::8>>, capabilities, session) do
+  defp decode_capability(
+         1,
+         <<afi::16, _reserved::8, safi::8>>,
+         %__MODULE__{} = capabilities,
+         session
+       ) do
     with {:ok, afi} <- AFN.decode_afi(afi),
          {:ok, safi} <- AFN.decode_safi(safi) do
-      {%__MODULE__{capabilities | multi_protocol: {afi, safi}}, session}
+      {%{capabilities | multi_protocol: {afi, safi}}, session}
     else
       :error ->
         raise NOTIFICATION, code: :open_message
     end
   end
 
-  defp decode_capability(2, <<>>, capabilities, session),
-    do: {%__MODULE__{capabilities | route_refresh: true}, session}
+  defp decode_capability(2, <<>>, %__MODULE__{} = capabilities, session),
+    do: {%{capabilities | route_refresh: true}, session}
 
-  defp decode_capability(6, <<>>, capabilities, session),
-    do: {%__MODULE__{capabilities | extended_message: true}, session}
+  defp decode_capability(6, <<>>, %__MODULE__{} = capabilities, session),
+    do: {%{capabilities | extended_message: true}, session}
 
   defp decode_capability(
          64,
          <<restarted::1, _reserved::3, time::12, afs::binary>>,
-         capabilities,
+         %__MODULE__{} = capabilities,
          session
        ),
        do:
-         {%__MODULE__{
+         {%{
             capabilities
             | graceful_restart: {restarted == 1, time, decode_afs(afs, [])}
           }, session}
 
-  defp decode_capability(65, <<asn::32>>, capabilities, session) do
+  defp decode_capability(65, <<asn::32>>, %__MODULE__{} = capabilities, %Session{} = session) do
     unless asn >= 1 and asn <= @asn_four_octets_max do
       raise NOTIFICATION,
         code: :open_message,
@@ -83,12 +88,12 @@ defmodule BGP.Message.OPEN.Capabilities do
         data: <<asn::size(32)>>
     end
 
-    {%__MODULE__{capabilities | four_octets_asn: true},
-     %Session{session | four_octets: true, ibgp: asn == session.asn}}
+    {%{capabilities | four_octets_asn: true},
+     %{session | four_octets: true, ibgp: asn == session.asn}}
   end
 
-  defp decode_capability(70, <<>>, capabilities, session),
-    do: {%__MODULE__{capabilities | enanched_route_refresh: true}, session}
+  defp decode_capability(70, <<>>, %__MODULE__{} = capabilities, session),
+    do: {%{capabilities | enanched_route_refresh: true}, session}
 
   defp decode_capability(_code, _data, _capabilities, _session) do
     raise NOTIFICATION, code: :open_message