[TYPO3-Solr] Index Queue Worker error after upgrade to 2.1.0

[Jan Slusarczyk]

I have upgraded to TER version 2.1.0 and indexing doesn't run with the 
following error in Scheduler:

Execution of task "Index Queue Worker (solr)" failed with the following 
message: PHP Catchable Fatal Error: Argument 1 passed to 
tx_solr_indexqueue_Queue::getIndexQueueItemObjectsFromRecords() must be 
an array, null given, called in 
xxx/typo3conf/ext/solr/classes/indexqueue/class.tx_solr_indexqueue_queue.php 
on line 538 and defined in 
xxx/typo3conf/ext/solr/classes/indexqueue/class.tx_solr_indexqueue_queue.php 
line 549

There's no error in Dev Log, only success notice on Index Queue 
initialization (1355 rows).

Any ideas what might be wrong?

Regards
Jan