diff --git a/pyprusalink/types.py b/pyprusalink/types.py
index 742d667..6f1340a 100644
--- a/pyprusalink/types.py
+++ b/pyprusalink/types.py
@@ -1,5 +1,5 @@
 from enum import Enum
-from typing import TypedDict
+from typing import NotRequired, TypedDict
 
 """Types of the v1 API. Source: https://github.com/prusa3d/Prusa-Link-Web/blob/master/spec/openapi.yaml"""
 
@@ -27,15 +27,40 @@ class Capabilities(TypedDict):
 
 
 class VersionInfo(TypedDict):
-    """Version data."""
+    """Version data from /api/version.
+
+    Field availability differs between PrusaLink variants and firmware versions:
+
+    Bundled PrusaLink (Prusa-Firmware-Buddy, all printers):
+      Always returned: api, server, nozzle_diameter, text, hostname, capabilities
+      Returned on v6.5.1+ only: firmware, printer
+        - v6.5.1 (2025-11-11): added on Core One L
+        - v6.5.3 (2026-03-24): propagated to Core One/MK4/MK3.9/MK3.5 family
+        - XL (6.4.x track) and MINI (6.4.0): not yet backported
+        - Source: https://github.com/prusa3d/Prusa-Firmware-Buddy/commit/64b7a21
+
+    Example response from MK4 firmware 6.4.0 (no firmware/printer fields):
+        {"api": "2.0.0", "server": "2.1.2", "nozzle_diameter": 0.4,
+         "text": "PrusaLink", "hostname": "prusa-mk4",
+         "capabilities": {"upload-by-put": True}}
+
+    Standalone PrusaLink (RPi-based installations):
+      May return version and sdk per the Prusa-Link-Web OpenAPI spec; these
+      are never returned by bundled firmware.
+
+    Use dict.get() for any field other than `api` to handle absence safely.
+    """
 
     api: str
-    version: str
-    printer: str
-    text: str
-    firmware: str
-    sdk: str | None
-    capabilities: Capabilities | None
+    text: NotRequired[str]
+    server: NotRequired[str]
+    hostname: NotRequired[str]
+    nozzle_diameter: NotRequired[float]
+    firmware: NotRequired[str]
+    printer: NotRequired[str]
+    version: NotRequired[str]
+    sdk: NotRequired[str]
+    capabilities: NotRequired[Capabilities]
 
 
 class PrinterInfo(TypedDict):
diff --git a/tests/test_prusalink.py b/tests/test_prusalink.py
index ceb87d4..085b3ee 100644
--- a/tests/test_prusalink.py
+++ b/tests/test_prusalink.py
@@ -6,21 +6,47 @@
 
 
 async def test_get_version(pl, respx_mock):
+    """Modern firmware (Buddy v6.5.1+) returns firmware and printer fields."""
     respx_mock.get(f"{HOST}/api/version").mock(
         return_value=httpx.Response(
             200,
             json={
                 "api": "2.0.0",
-                "version": "0.7.0",
-                "printer": "1.3.1",
-                "text": "PrusaLink 0.7.0",
-                "firmware": "3.10.1-4697",
+                "server": "2.1.2",
+                "nozzle_diameter": 0.40,
+                "text": "PrusaLink",
+                "hostname": "prusa-core-one",
+                "firmware": "6.5.3+12780",
+                "printer": "7.1.0",
+                "capabilities": {"upload-by-put": True},
             },
         )
     )
     result = await pl.get_version()
     assert result["api"] == "2.0.0"
-    assert result["firmware"] == "3.10.1-4697"
+    assert result["firmware"] == "6.5.3+12780"
+    assert result["printer"] == "7.1.0"
+
+
+async def test_get_version_legacy_firmware(pl, respx_mock):
+    """Legacy firmware (Buddy <v6.5.1, XL, MINI) omits firmware and printer fields."""
+    respx_mock.get(f"{HOST}/api/version").mock(
+        return_value=httpx.Response(
+            200,
+            json={
+                "api": "2.0.0",
+                "server": "2.1.2",
+                "nozzle_diameter": 0.40,
+                "text": "PrusaLink",
+                "hostname": "prusa-mk39",
+                "capabilities": {"upload-by-put": True},
+            },
+        )
+    )
+    result = await pl.get_version()
+    assert result["api"] == "2.0.0"
+    assert "firmware" not in result
+    assert "printer" not in result
 
 
 async def test_get_info(pl, respx_mock):