OSMC's May update is here

It does not.

The update resolves connectivity to shares that do not authenticate with ntlmv2 such as Time Capsules.

From cc75c0b5aa8d4efa5ba5ed746785a1fab57dcb03 Mon Sep 17 00:00:00 2001
From: Sam Nazarko <email@samnazarko.co.uk>
Date: Thu, 21 Apr 2016 13:40:20 +0100
Subject: [PATCH] Fix connectivity to weaker shares

Signed-off-by: Sam Nazarko <email@samnazarko.co.uk>
---
 xbmc/filesystem/SMBFile.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/xbmc/filesystem/SMBFile.cpp b/xbmc/filesystem/SMBFile.cpp
index 1f7af9b..4270e8c 100644
--- a/xbmc/filesystem/SMBFile.cpp
+++ b/xbmc/filesystem/SMBFile.cpp
@@ -121,6 +121,10 @@ void CSMB::Init()
         fprintf(f, "\tsocket options = TCP_NODELAY IPTOS_LOWDELAY SO_RCVBUF=65536 SO_SNDBUF=65536\n");      
         fprintf(f, "\tlock directory = %s/.smb/\n", home.c_str());
 
+        // post badlock fixes for legacy
+        fprintf(f, "\tclient use spnego = noclient\n");
+	fprintf(f, "\tntlmv2 auth = no\n");
+
         // set wins server if there's one. name resolve order defaults to 'lmhosts host wins bcast'.
         // if no WINS server has been specified the wins method will be ignored.
         if (CSettings::GetInstance().GetString(CSettings::SETTING_SMB_WINSSERVER).length() > 0 && !StringUtils::EqualsNoCase(CSettings::GetInstance().GetString(CSettings::SETTING_SMB_WINSSERVER), "0.0.0.0") )
-- 
2.7.4

The Samba maintainers have acknowledged that the latest version of Samba in Debian Jessie has regressions and that they will be addressed. I am not sure if this will restore Guest access to shares.

You should also note that Kodi’s implementation of Samba is based on Samba 3.x from 2013 era, but OSMC uses upstream Samba 4.x from Debian Jessie.

Sam