diff --git a/custom_components/sws12500/__init__.py b/custom_components/sws12500/__init__.py
index 931e411..f79746f 100644
--- a/custom_components/sws12500/__init__.py
+++ b/custom_components/sws12500/__init__.py
@@ -46,6 +46,7 @@ from .const import (
     ECOWITT_URL_PREFIX,
     HEALTH_URL,
     POCASI_CZ_ENABLED,
+    POCASI_CZ_ENABLED_LEGACY,
     SENSORS_TO_LOAD,
     WINDY_ENABLED,
     WSLINK,
@@ -61,6 +62,34 @@ from .staleness import update_stale_sensors_issue
 _LOGGER = logging.getLogger(__name__)
 PLATFORMS: list[Platform] = [Platform.SENSOR, Platform.BINARY_SENSOR]
 
+# Keep in sync with `ConfigFlowHandler.VERSION`.
+CONFIG_ENTRY_VERSION: int = 2
+
+
+async def async_migrate_entry(hass: HomeAssistant, entry: SWSConfigEntry) -> bool:
+    """Migrate an old config entry.
+
+    Version 2 renames the Pocasi Meteo enable flag from the misspelled
+    `pocasi_enabled_chcekbox` to `pocasi_enabled_checkbox`. Without moving the persisted
+    value, forwarding would silently switch off for every existing install.
+    """
+
+    if entry.version > CONFIG_ENTRY_VERSION:
+        # Downgrades are not supported - the entry was written by a newer version.
+        return False
+
+    if entry.version < 2:
+        options = dict(entry.options)
+        if POCASI_CZ_ENABLED_LEGACY in options:
+            legacy_value = options.pop(POCASI_CZ_ENABLED_LEGACY)
+            # Never clobber an already-correct key (both may exist after a partial upgrade).
+            options.setdefault(POCASI_CZ_ENABLED, legacy_value)
+            _LOGGER.debug("Migrated Pocasi Meteo enable flag to %s.", POCASI_CZ_ENABLED)
+
+        hass.config_entries.async_update_entry(entry, options=options, version=2)
+
+    return True
+
 
 def register_path(
     hass: HomeAssistant,
diff --git a/custom_components/sws12500/config_flow.py b/custom_components/sws12500/config_flow.py
index c27694b..3485db6 100644
--- a/custom_components/sws12500/config_flow.py
+++ b/custom_components/sws12500/config_flow.py
@@ -337,7 +337,7 @@ class ConfigFlowHandler(ConfigFlow, domain=DOMAIN):
         vol.Optional(DEV_DBG): bool,
     }
 
-    VERSION = 1
+    VERSION = 2
 
     async def async_step_user(self, user_input: Any = None):
         """Handle the initial step."""
diff --git a/custom_components/sws12500/const.py b/custom_components/sws12500/const.py
index 6e9aec9..ec40092 100644
--- a/custom_components/sws12500/const.py
+++ b/custom_components/sws12500/const.py
@@ -224,10 +224,14 @@ POCASI_CZ_API_KEY = "POCASI_CZ_API_KEY"
 POCASI_CZ_API_ID = "POCASI_CZ_API_ID"
 POCASI_CZ_SEND_INTERVAL = "POCASI_SEND_INTERVAL"
 POCASI_CZ_ENABLED = "pocasi_enabled_checkbox"
+# Misspelled key used by config entries created before version 2 (see `async_migrate_entry`).
+POCASI_CZ_ENABLED_LEGACY: Final = "pocasi_enabled_chcekbox"
 POCASI_CZ_LOGGER_ENABLED = "pocasi_logger_checkbox"
 POCASI_INVALID_KEY: Final = "Pocasi Meteo refused to accept data. Invalid ID/Key combination?"
 POCASI_CZ_SUCCESS: Final = "Successfully sent data to Pocasi Meteo"
-POCASI_CZ_UNEXPECTED: Final = "Pocasi Meteo responded unexpectedly 3 times in row. Resending is now disabled!"
+POCASI_CZ_UNEXPECTED: Final = (
+    f"Pocasi Meteo responded unexpectedly {POCASI_CZ_MAX_RETRIES} times in row. Resending is now disabled!"
+)
 
 WINDY_STATION_ID = "WINDY_STATION_ID"
 WINDY_STATION_PW = "WINDY_STATION_PWD"
@@ -238,7 +242,9 @@ WINDY_INVALID_KEY: Final = (
     "Windy API KEY is invalid. Send data to Windy is now disabled. Check your API KEY and try again."
 )
 WINDY_SUCCESS: Final = "Windy successfully sent data and data was successfully inserted by Windy API"
-WINDY_UNEXPECTED: Final = "Windy responded unexpectedly 3 times in a row. Send to Windy is now disabled!"
+WINDY_UNEXPECTED: Final = (
+    f"Windy responded unexpectedly {WINDY_MAX_RETRIES} times in a row. Send to Windy is now disabled!"
+)
 
 
 
diff --git a/custom_components/sws12500/pocasti_cz.py b/custom_components/sws12500/pocasti_cz.py
index ae7710a..ef9c54b 100644
--- a/custom_components/sws12500/pocasti_cz.py
+++ b/custom_components/sws12500/pocasti_cz.py
@@ -172,7 +172,7 @@ class PocasiPush:
                 self.last_error = f"Unexpected HTTP status {http_status} from Pocasi Meteo."
                 self.invalid_response_count += 1
                 _LOGGER.warning(
-                    "Unexpected HTTP status %s from Pocasi Meteo. Rentries before disabling resend: %s",
+                    "Unexpected HTTP status %s from Pocasi Meteo. Retries before disabling resend: %s",
                     http_status,
                     POCASI_CZ_MAX_RETRIES - self.invalid_response_count,
                 )
diff --git a/custom_components/sws12500/strings.json b/custom_components/sws12500/strings.json
index 23218fe..6f83c9d 100644
--- a/custom_components/sws12500/strings.json
+++ b/custom_components/sws12500/strings.json
@@ -110,14 +110,14 @@
           "POCASI_CZ_API_ID": "ID from your Pocasi Meteo APP",
           "POCASI_CZ_API_KEY": "Key from your Pocasi Meteo APP",
           "POCASI_SEND_INTERVAL": "Resend interval in seconds",
-          "pocasi_enabled_chcekbox": "Enable resending data to Pocasi Meteo",
+          "pocasi_enabled_checkbox": "Enable resending data to Pocasi Meteo",
           "pocasi_logger_checkbox": "Log data and responses"
         },
         "data_description": {
           "POCASI_CZ_API_ID": "You can obtain your ID in Pocasi Meteo App",
           "POCASI_CZ_API_KEY": "You can obtain your KEY in Pocasi Meteo App",
           "POCASI_SEND_INTERVAL": "Resend interval in seconds (minimum 12s, default 30s)",
-          "pocasi_enabled_chcekbox": "Enables resending data to Pocasi Meteo",
+          "pocasi_enabled_checkbox": "Enables resending data to Pocasi Meteo",
           "pocasi_logger_checkbox": "Enable only if you want to send debbug data to the developer"
         }
       },
diff --git a/custom_components/sws12500/translations/cs.json b/custom_components/sws12500/translations/cs.json
index 7bcd8ec..70b4076 100644
--- a/custom_components/sws12500/translations/cs.json
+++ b/custom_components/sws12500/translations/cs.json
@@ -110,14 +110,14 @@
           "POCASI_CZ_API_ID": "ID účtu na Počasí Meteo",
           "POCASI_CZ_API_KEY": "Klíč (Key) k účtu Počasí Meteo",
           "POCASI_SEND_INTERVAL": "Interval v sekundách",
-          "pocasi_enabled_chcekbox": "Povolit přeposílání dat na server Počasí Meteo",
+          "pocasi_enabled_checkbox": "Povolit přeposílání dat na server Počasí Meteo",
           "pocasi_logger_checkbox": "Logovat data a odpovědi z Počasí Meteo"
         },
         "data_description": {
           "POCASI_CZ_API_ID": "ID získáte ve své aplikaci Počasí Meteo",
           "POCASI_CZ_API_KEY": "Klíč (Key) získáte ve své aplikaci Počasí Meteo",
           "POCASI_SEND_INTERVAL": "Interval v jakém se mají data na server přeposílat (minimum 12s, defaultně 30s)",
-          "pocasi_enabled_chcekbox": "Zapne přeposílání data na server Počasí Meteo",
+          "pocasi_enabled_checkbox": "Zapne přeposílání data na server Počasí Meteo",
           "pocasi_logger_checkbox": "Zapnout pouze v případě, že chcete zaslat ladící informace vývojáři."
         }
       },
diff --git a/custom_components/sws12500/translations/en.json b/custom_components/sws12500/translations/en.json
index 23218fe..6f83c9d 100644
--- a/custom_components/sws12500/translations/en.json
+++ b/custom_components/sws12500/translations/en.json
@@ -110,14 +110,14 @@
           "POCASI_CZ_API_ID": "ID from your Pocasi Meteo APP",
           "POCASI_CZ_API_KEY": "Key from your Pocasi Meteo APP",
           "POCASI_SEND_INTERVAL": "Resend interval in seconds",
-          "pocasi_enabled_chcekbox": "Enable resending data to Pocasi Meteo",
+          "pocasi_enabled_checkbox": "Enable resending data to Pocasi Meteo",
           "pocasi_logger_checkbox": "Log data and responses"
         },
         "data_description": {
           "POCASI_CZ_API_ID": "You can obtain your ID in Pocasi Meteo App",
           "POCASI_CZ_API_KEY": "You can obtain your KEY in Pocasi Meteo App",
           "POCASI_SEND_INTERVAL": "Resend interval in seconds (minimum 12s, default 30s)",
-          "pocasi_enabled_chcekbox": "Enables resending data to Pocasi Meteo",
+          "pocasi_enabled_checkbox": "Enables resending data to Pocasi Meteo",
           "pocasi_logger_checkbox": "Enable only if you want to send debbug data to the developer"
         }
       },
diff --git a/custom_components/sws12500/windy_func.py b/custom_components/sws12500/windy_func.py
index 576f5c8..b983389 100644
--- a/custom_components/sws12500/windy_func.py
+++ b/custom_components/sws12500/windy_func.py
@@ -163,8 +163,10 @@ class WindyPush:
 
         `enabled` reads the option back, so persisting it here is what actually turns
         forwarding off.
+
+        `last_status` is deliberately left to the caller so the diagnostics sensor keeps
+        the specific reason (`config_error`, `auth_error`, ...) instead of a generic one.
         """
-        self.last_status = "disabled"
         self.last_error = reason
 
         if not await update_options(self.hass, self.config, WINDY_ENABLED, False):
@@ -251,7 +253,7 @@ class WindyPush:
 
                     # log despite of settings
                     _LOGGER.error(
-                        "%s Max rentries before disable resend function: %s",
+                        "%s Max retries before disable resend function: %s",
                         WINDY_NOT_INSERTED,
                         (WINDY_MAX_RETRIES - self.invalid_response_count),
                     )
@@ -268,7 +270,7 @@ class WindyPush:
                     self.last_status = "duplicate"
                     self.last_error = "Duplicate payload detected by Windy server."
                     _LOGGER.critical(
-                        "Duplicate payload detected by Windy server. Will try again later. Max rentries before disabling resend function: %s",
+                        "Duplicate payload detected by Windy server. Will try again later. Max retries before disabling resend function: %s",
                         (WINDY_MAX_RETRIES - self.invalid_response_count),
                     )
                     self.invalid_response_count += 1
@@ -296,7 +298,7 @@ class WindyPush:
                     self.invalid_response_count += 1
                     if self.log:
                         _LOGGER.debug(
-                            "Unexpected response from Windy. Max rentries before disabling resend function: %s",
+                            "Unexpected response from Windy. Max retries before disabling resend function: %s",
                             (WINDY_MAX_RETRIES - self.invalid_response_count),
                         )
                 finally:
@@ -306,7 +308,7 @@ class WindyPush:
                             WINDY_MAX_RETRIES,
                         )
                         await self._disable_windy(
-                            reason="Unable to send data to Windy (3 times). Disabling resend option for now. Please check your Windy configuration and enable this feature afterwards."
+                            reason=f"Unable to send data to Windy ({WINDY_MAX_RETRIES} times). Disabling resend option for now. Please check your Windy configuration and enable this feature afterwards."
                         )
 
         except ClientError as ex:
@@ -315,14 +317,16 @@ class WindyPush:
             # attributes; str(ex) could embed the request URL.
             self.last_error = type(ex).__name__
             _LOGGER.critical(
-                "Invalid response from Windy: %s. Will try again later, max rentries before disabling resend function: %s",
+                "Invalid response from Windy: %s. Will try again later, max retries before disabling resend function: %s",
                 str(ex),
                 (WINDY_MAX_RETRIES - self.invalid_response_count),
             )
             self.invalid_response_count += 1
             if self.invalid_response_count >= WINDY_MAX_RETRIES:
                 _LOGGER.critical(WINDY_UNEXPECTED)
-                await self._disable_windy(reason="Invalid response from Windy 3 times. Disabling resending option.")
+                await self._disable_windy(
+                    reason=f"Invalid response from Windy {WINDY_MAX_RETRIES} times. Disabling resending option."
+                )
         self.last_update = dt_util.utcnow()
         self.next_update = self.last_update + timed(minutes=5)
 
diff --git a/tests/test_const.py b/tests/test_const.py
index 7ad9732..0503b2f 100644
--- a/tests/test_const.py
+++ b/tests/test_const.py
@@ -1,4 +1,13 @@
-from custom_components.sws12500.const import DEFAULT_URL, DOMAIN, WINDY_URL, WSLINK_URL
+from custom_components.sws12500.const import (
+    DEFAULT_URL,
+    DOMAIN,
+    POCASI_CZ_MAX_RETRIES,
+    POCASI_CZ_UNEXPECTED,
+    WINDY_MAX_RETRIES,
+    WINDY_UNEXPECTED,
+    WINDY_URL,
+    WSLINK_URL,
+)
 
 
 def test_const_values():
@@ -6,3 +15,9 @@ def test_const_values():
     assert DEFAULT_URL == "/weatherstation/updateweatherstation.php"
     assert WSLINK_URL == "/data/upload.php"
     assert WINDY_URL == "https://stations.windy.com/api/v2/observation/update"
+
+
+def test_retry_counts_in_user_facing_messages():
+    """The retry count in the notification texts must follow the constants."""
+    assert f"{WINDY_MAX_RETRIES} times" in WINDY_UNEXPECTED
+    assert f"{POCASI_CZ_MAX_RETRIES} times" in POCASI_CZ_UNEXPECTED
diff --git a/tests/test_init.py b/tests/test_init.py
index 5e8fc01..56b9861 100644
--- a/tests/test_init.py
+++ b/tests/test_init.py
@@ -20,8 +20,19 @@ from unittest.mock import AsyncMock, MagicMock
 import pytest
 from pytest_homeassistant_custom_component.common import MockConfigEntry
 
-from custom_components.sws12500 import WeatherDataUpdateCoordinator, async_setup_entry
-from custom_components.sws12500.const import DOMAIN
+from custom_components.sws12500 import (
+    CONFIG_ENTRY_VERSION,
+    WeatherDataUpdateCoordinator,
+    async_migrate_entry,
+    async_setup_entry,
+)
+from custom_components.sws12500.config_flow import ConfigFlowHandler
+from custom_components.sws12500.const import (
+    DOMAIN,
+    POCASI_CZ_ENABLED,
+    POCASI_CZ_ENABLED_LEGACY,
+    WINDY_ENABLED,
+)
 from custom_components.sws12500.data import SWSRuntimeData
 from homeassistant.util import dt as dt_util
 
@@ -149,3 +160,83 @@ async def test_check_stale_callback_runs_update(
 
     captured["cb"](dt_util.utcnow())
     stale.assert_called_once_with(hass, config_entry)
+
+
+def test_config_flow_version_matches_migration_target() -> None:
+    """The flow version and the migration target must not drift apart."""
+    assert ConfigFlowHandler.VERSION == CONFIG_ENTRY_VERSION
+
+
+async def test_migrate_moves_legacy_pocasi_key(hass) -> None:
+    """A v1 entry carrying the misspelled key migrates to v2 keeping the value."""
+    entry = MockConfigEntry(
+        domain=DOMAIN,
+        data={},
+        options={POCASI_CZ_ENABLED_LEGACY: True, WINDY_ENABLED: True},
+        version=1,
+    )
+    entry.add_to_hass(hass)
+
+    assert await async_migrate_entry(hass, entry) is True
+
+    assert entry.version == 2
+    assert entry.options[POCASI_CZ_ENABLED] is True
+    assert POCASI_CZ_ENABLED_LEGACY not in entry.options
+    # Unrelated options survive untouched.
+    assert entry.options[WINDY_ENABLED] is True
+
+
+async def test_migrate_without_pocasi_option(hass) -> None:
+    """An entry that never had the Pocasi option migrates cleanly."""
+    entry = MockConfigEntry(domain=DOMAIN, data={}, options={WINDY_ENABLED: False}, version=1)
+    entry.add_to_hass(hass)
+
+    assert await async_migrate_entry(hass, entry) is True
+
+    assert entry.version == 2
+    assert POCASI_CZ_ENABLED not in entry.options
+    assert entry.options[WINDY_ENABLED] is False
+
+
+async def test_migrate_does_not_clobber_correct_key(hass) -> None:
+    """When both keys are present, the already-correct one wins."""
+    entry = MockConfigEntry(
+        domain=DOMAIN,
+        data={},
+        options={POCASI_CZ_ENABLED_LEGACY: False, POCASI_CZ_ENABLED: True},
+        version=1,
+    )
+    entry.add_to_hass(hass)
+
+    assert await async_migrate_entry(hass, entry) is True
+
+    assert entry.options[POCASI_CZ_ENABLED] is True
+    assert POCASI_CZ_ENABLED_LEGACY not in entry.options
+
+
+async def test_migrate_is_idempotent(hass) -> None:
+    """Running the migration twice leaves the entry unchanged."""
+    entry = MockConfigEntry(
+        domain=DOMAIN, data={}, options={POCASI_CZ_ENABLED_LEGACY: True}, version=1
+    )
+    entry.add_to_hass(hass)
+
+    assert await async_migrate_entry(hass, entry) is True
+    first = dict(entry.options)
+
+    assert await async_migrate_entry(hass, entry) is True
+
+    assert entry.version == 2
+    assert dict(entry.options) == first
+    assert entry.options[POCASI_CZ_ENABLED] is True
+
+
+async def test_migrate_refuses_future_version(hass) -> None:
+    """An entry written by a newer version is not downgraded."""
+    entry = MockConfigEntry(
+        domain=DOMAIN, data={}, options={}, version=CONFIG_ENTRY_VERSION + 1
+    )
+    entry.add_to_hass(hass)
+
+    assert await async_migrate_entry(hass, entry) is False
+    assert entry.version == CONFIG_ENTRY_VERSION + 1
diff --git a/tests/test_windy_push.py b/tests/test_windy_push.py
index 890118c..6a6d7db 100644
--- a/tests/test_windy_push.py
+++ b/tests/test_windy_push.py
@@ -232,6 +232,8 @@ async def test_push_data_to_windy_missing_station_id_returns_false(monkeypatch,
     ok = await wp.push_data_to_windy({"a": "b"})
     assert ok is False
     assert session.calls == []
+    # Disabling must not overwrite the specific reason the diagnostics sensor reports.
+    assert wp.last_status == "config_error"
 
 
 @pytest.mark.asyncio
@@ -259,6 +261,7 @@ async def test_push_data_to_windy_missing_station_pw_returns_false(monkeypatch,
     ok = await wp.push_data_to_windy({"a": "b"})
     assert ok is False
     assert session.calls == []
+    assert wp.last_status == "config_error"
 
 
 @pytest.mark.asyncio
@@ -288,6 +291,7 @@ async def test_push_data_to_windy_invalid_api_key_disables_windy(monkeypatch, ha
     ok = await wp.push_data_to_windy({"a": "b"})
     assert ok is True
     update_options.assert_awaited_once_with(hass, entry, WINDY_ENABLED, False)
+    assert wp.last_status == "auth_error"
 
 
 @pytest.mark.asyncio