Do not worry about the addresses in the offline client...
Create the TX with a watch online 2.5.4 client. The sign with the 2.5.4 offline client.
Just download the 2.5.4 tarball and extract the tarball then run ./electrum from the directory. No need to install anything...
Thanks a lot! It helped, I was trying to sign with an Electrum 2.5.4 a transaction created by Electrum 1.9.8 assuming that they should be identical except the signature part (especially given that 2.5.4 successfully decodes transaction created by 1.9.8 ). It turned out they are not. Thanks again.
Out of curiosity, would you mind to explain what's the difference between them. I took a look at json files and 2.5.4 version doesn't contain "input_info" field, but 2.5.4 shouldn't pay attention to that field anyway, since 2.5.4 version doesn't contain it.