diff --git a/docs/src/manpage.md b/docs/src/manpage.md
index d1e17037a..de062eeb9 100644
--- a/docs/src/manpage.md
+++ b/docs/src/manpage.md
@@ -2240,10 +2240,10 @@ FUNCTIONS FOR FILTER/PUT
         (class=typing #args=1) True if argument is not a map.
 
    is_not_null
-        (class=typing #args=1) False if argument is null (empty or absent), true otherwise.
+        (class=typing #args=1) False if argument is null (empty, absent, or JSON null), true otherwise.
 
    is_null
-        (class=typing #args=1) True if argument is null (empty or absent), false otherwise.
+        (class=typing #args=1) True if argument is null (empty, absent, or JSON null), false otherwise.
 
    is_numeric
         (class=typing #args=1) True if field is present with value inferred to be int or float
@@ -3086,5 +3086,5 @@ SEE ALSO
 
 
 
-                                  2022-01-16                         MILLER(1)
+                                  2022-01-20                         MILLER(1)
 </pre>
diff --git a/docs/src/manpage.txt b/docs/src/manpage.txt
index a43f6add0..68c443582 100644
--- a/docs/src/manpage.txt
+++ b/docs/src/manpage.txt
@@ -2219,10 +2219,10 @@ FUNCTIONS FOR FILTER/PUT
         (class=typing #args=1) True if argument is not a map.
 
    is_not_null
-        (class=typing #args=1) False if argument is null (empty or absent), true otherwise.
+        (class=typing #args=1) False if argument is null (empty, absent, or JSON null), true otherwise.
 
    is_null
-        (class=typing #args=1) True if argument is null (empty or absent), false otherwise.
+        (class=typing #args=1) True if argument is null (empty, absent, or JSON null), false otherwise.
 
    is_numeric
         (class=typing #args=1) True if field is present with value inferred to be int or float
@@ -3065,4 +3065,4 @@ SEE ALSO
 
 
 
-                                  2022-01-16                         MILLER(1)
+                                  2022-01-20                         MILLER(1)
diff --git a/docs/src/reference-dsl-builtin-functions.md b/docs/src/reference-dsl-builtin-functions.md
index 3b10128d4..1b4e46399 100644
--- a/docs/src/reference-dsl-builtin-functions.md
+++ b/docs/src/reference-dsl-builtin-functions.md
@@ -1464,13 +1464,13 @@ is_not_map  (class=typing #args=1) True if argument is not a map.
 
 ### is_not_null
 <pre class="pre-non-highlight-non-pair">
-is_not_null  (class=typing #args=1) False if argument is null (empty or absent), true otherwise.
+is_not_null  (class=typing #args=1) False if argument is null (empty, absent, or JSON null), true otherwise.
 </pre>
 
 
 ### is_null
 <pre class="pre-non-highlight-non-pair">
-is_null  (class=typing #args=1) True if argument is null (empty or absent), false otherwise.
+is_null  (class=typing #args=1) True if argument is null (empty, absent, or JSON null), false otherwise.
 </pre>
 
 
diff --git a/internal/pkg/auxents/help/entry.go b/internal/pkg/auxents/help/entry.go
index 8b362f4c7..ad6b41a23 100644
--- a/internal/pkg/auxents/help/entry.go
+++ b/internal/pkg/auxents/help/entry.go
@@ -712,8 +712,7 @@ func helpByApproximateSearchOne(thing string) bool {
 	}
 
 	if !found {
-		fmt.Printf("No help found for \"%s\". Please try 'mlr help find %s' for approximate match.\n", thing, thing)
-		fmt.Printf("See also 'mlr help topics'.\n")
+		fmt.Printf("No help found for \"%s\". See also 'mlr help topics'.\n", thing)
 	}
 	return found
 }
diff --git a/man/manpage.txt b/man/manpage.txt
index a43f6add0..68c443582 100644
--- a/man/manpage.txt
+++ b/man/manpage.txt
@@ -2219,10 +2219,10 @@ FUNCTIONS FOR FILTER/PUT
         (class=typing #args=1) True if argument is not a map.
 
    is_not_null
-        (class=typing #args=1) False if argument is null (empty or absent), true otherwise.
+        (class=typing #args=1) False if argument is null (empty, absent, or JSON null), true otherwise.
 
    is_null
-        (class=typing #args=1) True if argument is null (empty or absent), false otherwise.
+        (class=typing #args=1) True if argument is null (empty, absent, or JSON null), false otherwise.
 
    is_numeric
         (class=typing #args=1) True if field is present with value inferred to be int or float
@@ -3065,4 +3065,4 @@ SEE ALSO
 
 
 
-                                  2022-01-16                         MILLER(1)
+                                  2022-01-20                         MILLER(1)
diff --git a/man/mlr.1 b/man/mlr.1
index 7a716cde9..ff56bc994 100644
--- a/man/mlr.1
+++ b/man/mlr.1
@@ -2,12 +2,12 @@
 .\"     Title: mlr
 .\"    Author: [see the "AUTHOR" section]
 .\" Generator: ./mkman.rb
-.\"      Date: 2022-01-16
+.\"      Date: 2022-01-20
 .\"    Manual: \ \&
 .\"    Source: \ \&
 .\"  Language: English
 .\"
-.TH "MILLER" "1" "2022-01-16" "\ \&" "\ \&"
+.TH "MILLER" "1" "2022-01-20" "\ \&" "\ \&"
 .\" -----------------------------------------------------------------
 .\" * Portability definitions
 .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -3242,7 +3242,7 @@ gmt2sec("2001-02-03T04:05:06Z") = 981173106
 .RS 0
 .\}
 .nf
- (class=typing #args=1) False if argument is null (empty or absent), true otherwise.
+ (class=typing #args=1) False if argument is null (empty, absent, or JSON null), true otherwise.
 .fi
 .if n \{\
 .RE
@@ -3251,7 +3251,7 @@ gmt2sec("2001-02-03T04:05:06Z") = 981173106
 .RS 0
 .\}
 .nf
- (class=typing #args=1) True if argument is null (empty or absent), false otherwise.
+ (class=typing #args=1) True if argument is null (empty, absent, or JSON null), false otherwise.
 .fi
 .if n \{\
 .RE
diff --git a/test/cases/help/0008/expout b/test/cases/help/0008/expout
index b39493a58..612a8b397 100644
--- a/test/cases/help/0008/expout
+++ b/test/cases/help/0008/expout
@@ -1,2 +1 @@
-No help found for "nonesuch". Please try 'mlr help find nonesuch' for approximate match.
-See also 'mlr help topics'.
+No help found for "nonesuch". See also 'mlr help topics'.
diff --git a/test/cases/help/0009/expout b/test/cases/help/0009/expout
index 1e09eb9ec..91c93ce65 100644
--- a/test/cases/help/0009/expout
+++ b/test/cases/help/0009/expout
@@ -1,5 +1,4 @@
-No help found for "nonesuch". Please try 'mlr help find nonesuch' for approximate match.
-See also 'mlr help topics'.
+No help found for "nonesuch". See also 'mlr help topics'.
 asin  (class=math #args=1) Inverse trigonometric sine.
 asinh  (class=math #args=1) Inverse hyperbolic sine.
 sin  (class=math #args=1) Trigonometric sine.
diff --git a/test/cases/help/0018/expout b/test/cases/help/0018/expout
index 560401525..55b7d1da7 100644
--- a/test/cases/help/0018/expout
+++ b/test/cases/help/0018/expout
@@ -2,5 +2,4 @@
 Use CSV format for input and output data.
 --csvlite
 Use CSV-lite format for input and output data.
-No help found for "--csv". Please try 'mlr help find --csv' for approximate match.
-See also 'mlr help topics'.
+No help found for "--csv". See also 'mlr help topics'.