Torch/nn update breaks loading OpenNMT models trained with earlier version(?)

Having recently updated our torch installation and packages we are no longer able to load the models that were trained using the old version:

$ translate.lua -model model_old.t7 …

[05/24/17 08:50:38 INFO] Loading ‘model_old.t7’…
[05/24/17 08:50:47 INFO] Model seq2seq trained on bitext
…/torch/install/bin/lua: …e/local/src/torch/install/share/lua/5.2/nn/JoinTable.lua:38: bad argument #1 to ‘copy’ (sizes do not match at /tmp/luarocks_cutorch-scm-1-5403/cutorch/lib/THC/

Models trained in current setup work fine. Is it expected behaviour or does anoyne have some similar experience?

Hello, we are trying to be careful with backward compatibility. Do you know with which version of OpenNMT you trained the “old models”?

Related to:

On which version did you train model_old.t7 and with what options?

I used the same OpenNMT version for the “old” models as I’m using now, in which the last commit is 6521cc0cd4d64d07bb4d94ca2b99787f1cd66b7d, Wed Apr 19 12:23:11. It’s only the torch (and its packages) installation that I updated, with ‘old version’ I was referring (pretty misleadingly, sorry for that) to the torch stuff.

Training options (it’s just a toy model):

-src_vocab_size 50000 -tgt_vocab_size 50000 -src_seq_length 80 -tgt_seq_length 80
-brnn -layers 2 -rnn_size 500 -rnn_type LSTM -word_vec_size 500 -feat_vec_exponent 0.8 -max_batch_size 32 -input_feed 1
-end_epoch 18 -optim sgd -learning_rate 1 -dropout 0.3 -learning_rate_decay 0.5 -start_decay_at 9 -curriculum 0


thanks for your great support!
now, just need to be upgraded nn,It worked fine.
luarocks install nn

Thanks, all is back to normal now.