We decided to wait and upgrade Omeka from 1.5.2 to 2 when it is ready. However, we have a message in admin site saying "A new version of Omeka is available for download. Upgrade to 1.5.3" I wonder how I can hide the message so our creators do not bother with it!.
I solved this too -- for others who might wonder, go to /admin/themes/default/index.php (assuming you're using the default admin theme, of course) and comment out these lines:
<?php // Retrieve the latest version of Omeka by pinging the Omeka server. ?>
<?php if (has_permission('Upgrade', 'index')):
$latestVersion = get_latest_omeka_version();
if ($latestVersion and version_compare(OMEKA_VERSION, $latestVersion, '<')): ?>
<?php echo __('A new version of Omeka is available for download.'); ?>
<?php echo __('Upgrade to %s', $latestVersion); ?>