diff --git a/graylog-metrics/2.3/graylog_input_metrics-0.4.0.mkp b/graylog-metrics/2.3/graylog_input_metrics-0.4.0.mkp
new file mode 100755
index 0000000..3a5b238
Binary files /dev/null and b/graylog-metrics/2.3/graylog_input_metrics-0.4.0.mkp differ
diff --git a/graylog-metrics/local/lib/python3/cmk/gui/plugins/wato/check_parameters/graylog_input_metrics.py b/graylog-metrics/2.3/local/lib/python3/cmk/gui/plugins/wato/check_parameters/graylog_input_metrics.py
similarity index 98%
rename from graylog-metrics/local/lib/python3/cmk/gui/plugins/wato/check_parameters/graylog_input_metrics.py
rename to graylog-metrics/2.3/local/lib/python3/cmk/gui/plugins/wato/check_parameters/graylog_input_metrics.py
index 89e9057..a92ebe5 100644
--- a/graylog-metrics/local/lib/python3/cmk/gui/plugins/wato/check_parameters/graylog_input_metrics.py
+++ b/graylog-metrics/2.3/local/lib/python3/cmk/gui/plugins/wato/check_parameters/graylog_input_metrics.py
@@ -21,7 +21,7 @@ mappings={
     "im": "messages",
     "rs": "bytes",
     "upper": "above",
-    "lower": "below",
+    "lower": "below or equal",
 }
 
 
diff --git a/graylog-metrics/local/lib/python3/cmk/special_agents/agent_graylog_input_metrics.py b/graylog-metrics/2.3/local/lib/python3/cmk/special_agents/agent_graylog_input_metrics.py
similarity index 100%
rename from graylog-metrics/local/lib/python3/cmk/special_agents/agent_graylog_input_metrics.py
rename to graylog-metrics/2.3/local/lib/python3/cmk/special_agents/agent_graylog_input_metrics.py
diff --git a/graylog-metrics/local/share/check_mk/agents/special/agent_graylog_input_metrics b/graylog-metrics/2.3/local/share/check_mk/agents/special/agent_graylog_input_metrics
similarity index 100%
rename from graylog-metrics/local/share/check_mk/agents/special/agent_graylog_input_metrics
rename to graylog-metrics/2.3/local/share/check_mk/agents/special/agent_graylog_input_metrics
diff --git a/graylog-metrics/local/share/check_mk/checks/agent_graylog_input_metrics b/graylog-metrics/2.3/local/share/check_mk/checks/agent_graylog_input_metrics
similarity index 100%
rename from graylog-metrics/local/share/check_mk/checks/agent_graylog_input_metrics
rename to graylog-metrics/2.3/local/share/check_mk/checks/agent_graylog_input_metrics
diff --git a/graylog-metrics/local/share/check_mk/checks/graylog_input_metrics b/graylog-metrics/2.3/local/share/check_mk/checks/graylog_input_metrics
similarity index 56%
rename from graylog-metrics/local/share/check_mk/checks/graylog_input_metrics
rename to graylog-metrics/2.3/local/share/check_mk/checks/graylog_input_metrics
index 9c3483a..21dafd1 100644
--- a/graylog-metrics/local/share/check_mk/checks/graylog_input_metrics
+++ b/graylog-metrics/2.3/local/share/check_mk/checks/graylog_input_metrics
@@ -7,7 +7,7 @@
 # resolving legacy discovery results such as [("SUMMARY", "diskstat_default_levels")]. Furthermore,
 # it might also remove variables needed for accessing discovery rulesets.
 import json
-from cmk.base.check_api import check_levels, LegacyCheckDefinition
+from cmk.base.check_api import LegacyCheckDefinition
 from cmk.base.config import check_info
 from cmk.agent_based.v2 import Service
 
@@ -74,6 +74,79 @@ def check_graylog_input_metrics(item, params, parsed):
             infoname=infotext
         )
 
+
+# A customer wanted us to support <= for "below", not <. This meant copying
+# check_levels() and child functions wholesale out of
+# lib/python3/cmk/base/check_api.py just to change < to <= in this function.
+# Sometimes a sledgehammer is what it takes... D:
+# Start copy ===================================================================
+from cmk.agent_based import v1 as _v1
+
+def _do_check_levels(value, levels, human_readable_func):
+    warn_upper, crit_upper, warn_lower, crit_lower = levels
+
+    # Critical cases
+    if crit_upper is not None and value >= crit_upper:
+        return 2, _levelsinfo_ty("at", warn_upper, crit_upper, human_readable_func)
+    if crit_lower is not None and value <= crit_lower:
+        return 2, _levelsinfo_ty("below", warn_lower, crit_lower, human_readable_func)
+
+    # Warning cases
+    if warn_upper is not None and value >= warn_upper:
+        return 1, _levelsinfo_ty("at", warn_upper, crit_upper, human_readable_func)
+    if warn_lower is not None and value <= warn_lower:
+        return 1, _levelsinfo_ty("below", warn_lower, crit_lower, human_readable_func)
+    return 0, ""
+
+def _levelsinfo_ty(ty, warn, crit, human_readable_func):
+    warn_str = "never" if warn is None else f"{human_readable_func(warn)}"
+    crit_str = "never" if crit is None else f"{human_readable_func(crit)}"
+    return f" (warn/crit {ty} {warn_str}/{crit_str})"
+
+def _build_perfdata(dsname, value, levels, boundaries):
+    used_boundaries = boundaries if isinstance(boundaries, tuple) and len(boundaries) == 2 else ()
+    return [(dsname, value, levels[0], levels[1], *used_boundaries)]
+
+def check_levels(value, dsname, params, unit, human_readable_func, infoname, boundaries=None):
+    def render_func(x):
+        return "%s%s" % (human_readable_func(x), unit)
+
+    if params and isinstance(params, dict):
+        result, *metrics = _v1.check_levels_predictive(
+            value,
+            levels=params,
+            metric_name=dsname,
+            render_func=render_func,
+            label=infoname,
+            boundaries=boundaries,
+        )
+        assert isinstance(result, _v1.Result)
+        return (
+            int(result.state),
+            result.summary,
+            [
+                (m.name, m.value, *m.levels, *m.boundaries)
+                for m in metrics
+                if isinstance(m, _v1.Metric)
+            ],
+        )
+
+    infotext = f"{render_func(value)}"
+    if infoname:
+        infotext = f"{infoname}: {infotext}"
+
+    levels = params
+
+    state, levelstext = _do_check_levels(value, levels, render_func)
+    state, levelstext = _do_check_levels(value, levels, render_func)
+    return (
+        state,
+        infotext + levelstext,
+        _build_perfdata(dsname, value, levels, boundaries),
+    )
+# End copy ====================================================================
+
+
 check_info["graylog_input_metrics"] =  LegacyCheckDefinition(
     parse_function = parse_graylog_input_metrics,
     check_function = check_graylog_input_metrics,
diff --git a/graylog-metrics/local/share/check_mk/web/plugins/wato/graylog_input_metrics.py b/graylog-metrics/2.3/local/share/check_mk/web/plugins/wato/graylog_input_metrics.py
similarity index 100%
rename from graylog-metrics/local/share/check_mk/web/plugins/wato/graylog_input_metrics.py
rename to graylog-metrics/2.3/local/share/check_mk/web/plugins/wato/graylog_input_metrics.py
diff --git a/graylog-metrics/graylog_input_metrics-0.0.3.mkp b/graylog-metrics/graylog_input_metrics-0.0.3.mkp
deleted file mode 100644
index f38c5ba..0000000
Binary files a/graylog-metrics/graylog_input_metrics-0.0.3.mkp and /dev/null differ