I have been updating the extensions as they become available. Site import extension was just released an I went through the update procedure, only this time I received the message, "A newer version of file ... already exists. Do you want to replace this."
I assumed I was to say no since I had just updated some other extensions and I didn't want to mess one of those up by replacing newer files with older files. To my chagrin I discovered there are 1,461,253 files to be replaced, ... well it felt like that many after clinking no for 10 minutes.
What is the proper procedure for upgrading these extensions? There will be several more to do and I expect I'll be running into this problem again.