diff --git a/lib/net/imap.rb b/lib/net/imap.rb
index 54d060e3..7223d70b 100644
--- a/lib/net/imap.rb
+++ b/lib/net/imap.rb
@@ -1603,7 +1603,7 @@ def list(refname, mailbox)
     #
     # ==== Capabilities
     #
-    # The server's capabilities must include +NAMESPACE+
+    # The server's capabilities must include either +IMAP4rev2+ or +NAMESPACE+
     # [RFC2342[https://tools.ietf.org/html/rfc2342]].
     def namespace
       synchronize do
@@ -1904,7 +1904,7 @@ def close
     #
     # ==== Capabilities
     #
-    # The server's capabilities must include +UNSELECT+
+    # The server's capabilities must include either +IMAP4rev2+ or +UNSELECT+
     # [RFC3691[https://tools.ietf.org/html/rfc3691]].
     def unselect
       send_command("UNSELECT")
@@ -2647,7 +2647,7 @@ def uid_copy(set, mailbox)
     #
     # ==== Capabilities
     #
-    # The server's capabilities must include +MOVE+
+    # The server's capabilities must include either +IMAP4rev2+ or +MOVE+
     # [RFC6851[https://tools.ietf.org/html/rfc6851]].
     #
     # If +UIDPLUS+ [RFC4315[https://www.rfc-editor.org/rfc/rfc4315.html]] is
@@ -2889,7 +2889,7 @@ def enable(*capabilities)
     #
     # ==== Capabilities
     #
-    # The server's capabilities must include +IDLE+
+    # The server's capabilities must include either +IMAP4rev2+ or +IDLE+
     # [RFC2177[https://tools.ietf.org/html/rfc2177]].
     def idle(timeout = nil, &response_handler)
       raise LocalJumpError, "no block given" unless response_handler
diff --git a/lib/net/imap/search_result.rb b/lib/net/imap/search_result.rb
index 02164dec..67177c8c 100644
--- a/lib/net/imap/search_result.rb
+++ b/lib/net/imap/search_result.rb
@@ -100,10 +100,10 @@ def inspect
       #    data.to_s("SORT")   # => "* SORT 2 8 32 128 256 512"
       #    data.to_s(nil)      # => "2 8 32 128 256 512"
       #
-      #    data = Net::IMAP::SearchResult[1, 3, 16, 1024, modseq: 2048].to_s
+      #    data = Net::IMAP::SearchResult[1, 3, 16, 1024, modseq: 2048]
       #    data.to_s           # => "* SEARCH 1 3 16 1024 (MODSEQ 2048)"
       #    data.to_s("SORT")   # => "* SORT 1 3 16 1024 (MODSEQ 2048)"
-      #    data.to_s           # => "1 3 16 1024 (MODSEQ 2048)"
+      #    data.to_s(nil)      # => "1 3 16 1024 (MODSEQ 2048)"
       #
       def to_s(type = "SEARCH")
         str = +""