diff --git a/CHANGELOG b/CHANGELOG
index 6e6574ce..1c38d55a 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,5 @@
+0.58.8
+ - enh: existence of "index_online" section is no longer required
 0.58.7
  - enh: introduce `RTDCBase.features_local` for accessing features
    that are exclusively local and not in remote locations
diff --git a/dclab/rtdc_dataset/check.py b/dclab/rtdc_dataset/check.py
index c36a009f..2bf9ea18 100644
--- a/dclab/rtdc_dataset/check.py
+++ b/dclab/rtdc_dataset/check.py
@@ -18,7 +18,6 @@
 DESIRABLE_SECTIONS = {
     "experiment",
     "imaging",
-    "online_contour",
     "setup",
 }
 
@@ -98,10 +97,6 @@
         "temperature",
         "chip identifier",
     ],
-    "online_contour": [
-        # introduced in 0.34.0
-        "bg empty",
-    ],
 }
 
 #: valid metadata choices
diff --git a/dclab/rtdc_dataset/writer.py b/dclab/rtdc_dataset/writer.py
index 7ce2f06a..a72a297e 100644
--- a/dclab/rtdc_dataset/writer.py
+++ b/dclab/rtdc_dataset/writer.py
@@ -215,7 +215,7 @@ def store_basin(self,
             If this is an integer numpy array, it defines the mapping
             of event indices from the basin dataset to the referring dataset
             (the dataset being written to disk). Normally, the basinmap
-            feature used for the storing the mapping information is inferred
+            feature used for storing the mapping information is inferred
             from the currently defined basinmap features. However, if you
             are incepting basins, then this might not be sufficient, and you
             have to specify explicitly which basinmap feature to use. In such