21CN and ISDN
Unless I've misread the article, I believe it to be quite misleading. Yes, old ISDN products are being "retired", but they're being replaced by ISDN2e, ISDN30 and ISDN30e.
See http://www.switchedonuk.org/corporate/product/ for information on product retirements and replacements within 21CN.
You can also see BT Wholesale's plans for ISDN migrations on to 21CN all over the btwholesale.com/consult21 website. For example, in a powerpoint slide show not even two weeks old BT were discussing ISDN migrations (See Slide 15, Steering Borad Slides, http://www.btwholesale.com/content/binaries/21_Century_Network_Community/C21_SB_output_310707v1.zip)
Sure, I don't doubt that the eventual plan is to knock ISDN on the head at *some point*, but it's certainly not going to be any time soon!