This remark made me think of streams that were produced with release 1 of the Streams library, and if we should provide conversion facilities to the release 2 data structure.
This is what I found:
- Any streams produced with release 1 (and perhaps saved to a variable) can be read by rel. 2 blocks;
- Any (partly) evaluated rel. 1 streams will be fully re-evaluated by rel. 2 blocks though;
- Any streams produced by rel. 2 blocks are incompatible cannot be processed by rel. 1 blocks. Any conversion be unsatisfying as the original item 2 (rel. 1) of any yet evaluated part of a rel. 2 stream cannot be reconstructed from the available data.
IMO mentioning the above findings in online Help (I am systematically referring to the help text of tail of stream) will suffice.