Upgraded 1.5.3. to 2.1.2, now custom exhibit layouts don't display

I've looked through some of the other recent upgrade threads, but haven't seen quite the same problem. Upgrading Omeka and the database seem to have gone fine, but I have a number of custom exhibit layouts from the old version that aren't displaying properly, and I can't edit the exhibit pages either.

I got the following error report when I tried to edit:

#0 /home/robinduckworth/exhibits-staging.congregationallibrary.org/application/libraries/Zend/Config/Ini.php(202): Zend_Config_Ini->_parseIniFile('/home/robinduck...')
#1 /home/robinduckworth/exhibits-staging.congregationallibrary.org/application/libraries/Zend/Config/Ini.php(126): Zend_Config_Ini->_loadIniFile('/home/robinduck...')
#2 /home/robinduckworth/exhibits-staging.congregationallibrary.org/plugins/ExhibitBuilder/helpers/ExhibitFunctions.php(364): Zend_Config_Ini->__construct('/home/robinduck...', 'layout')
#3 /home/robinduckworth/exhibits-staging.congregationallibrary.org/plugins/ExhibitBuilder/views/admin/exhibits/page-metadata-form.php(41): exhibit_builder_layout()
#4 /home/robinduckworth/exhibits-staging.congregationallibrary.org/application/libraries/Omeka/View.php(117): include('/home/robinduck...')
#5 /home/robinduckworth/exhibits-staging.congregationallibrary.org/application/libraries/Zend/View/Abstract.php(888): Omeka_View->_run('text-banner-top')
#6 /home/robinduckworth/exhibits-staging.congregationallibrary.org/application/libraries/Zend/Controller/Action/Helper/ViewRenderer.php(900): Zend_View_Abstract->render('/home/robinduck...')
#7 /home/robinduckworth/exhibits-staging.congregationallibrary.org/application/libraries/Zend/Controller/Action/Helper/ViewRenderer.php(921): Zend_Controller_Action_Helper_ViewRenderer->renderScript('exhibits/page-m...')
#8 /home/robinduckworth/exhibits-staging.congregationallibrary.org/application/libraries/Zend/Controller/Action.php(212): Zend_Controller_Action_Helper_ViewRenderer->render('exhibits/page-m...', NULL)
#9 /home/robinduckworth/exhibits-staging.congregationallibrary.org/plugins/ExhibitBuilder/controllers/ExhibitsController.php(335): Zend_Controller_Action->render('page-metadata-f...', NULL, false)
#10 /home/robinduckworth/exhibits-staging.congregationallibrary.org/application/libraries/Zend/Controller/Action.php(516): ExhibitBuilder_ExhibitsController->editPageMetadataAction('page-metadata-f...')
#11 /home/robinduckworth/exhibits-staging.congregationallibrary.org/application/libraries/Zend/Controller/Dispatcher/Standard.php(308): Zend_Controller_Action->dispatch()
#12 /home/robinduckworth/exhibits-staging.congregationallibrary.org/application/libraries/Zend/Controller/Front.php(954): Zend_Controller_Dispatcher_Standard->dispatch('editPageMetadat...')
#13 /home/robinduckworth/exhibits-staging.congregationallibrary.org/application/libraries/Zend/Application/Bootstrap/Bootstrap.php(97): Zend_Controller_Front->dispatch(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http))
#14 /home/robinduckworth/exhibits-staging.congregationallibrary.org/application/libraries/Zend/Application.php(366): Zend_Application_Bootstrap_Bootstrap->run()
#15 /home/robinduckworth/exhibits-staging.congregationallibrary.org/application/libraries/Omeka/Application.php(79): Zend_Application->run()
#16 /home/robinduckworth/exhibits-staging.congregationallibrary.org/admin/index.php(28): Omeka_Application->run()
#17 {main}

...and the public page http://exhibits-staging.congregationallibrary.org/exhibits/show/abcfm200/intro/splash) is only showing:

Fatal error: Call to undefined function exhibit_builder_display_exhibit_thumbnail_gallery() in /home/robinduckworth/exhibits-staging.congregationallibrary.org/plugins/ExhibitBuilder/views/shared/exhibit_layouts/thumbnails-6x2-image-text/layout.php on line 4

...which is what's leading me to believe that 2.1.2 is having problems with my layouts. Is there an easy way to fix this, or do I need to build new versions from scratch?

Hard to tell exactly how extensive the updates will be, but there will be a fair amount.

Most notably, for Omeka 2.x the Exhibit Builder no longer uses sections in the structure. You will just have the Exhibit, and Exhibit Pages, which can include child pages. So, that will be a big change to make in your layouts and forms.

Several of the functions used have also changed, both in Omeka 2.x and in the updated ExhibitBuilder. For example, exhibit() is no longer used, in favor of the general new metadata() function in Omeka 2.x core.

This page will show the changes in Omeka 2.x core functions, which are used in the new ExhibitBuilder. Other changes in EB follow similar patterns, for example in the looping structure.

Ah.

In that case, it looks like the old find-and-replace is probably the best place to start for the functions in the custom layouts, and then I can adjust the actual exhibit structure as needed.

Thanks.