Retrain with new tags?

[jbkoh]

Hi,

I am trying to do some transfer-learning framework with CRF. I would like to use the "retrain" feature but CRFSharp requires the pretrained model to have all tags in new learning samples. I could manually put all labels at the first learning, but once a new model is trained upon an existing model, it only contains the tags in the new samples.

Is there a way to keep tags in pretrained model at the target model?
Or even better, is there a way to provide possible tags at the encoding stage separately?