We have a Scrum Team of a Product Owner and four developers (one of whom is Scrum Master), running one week sprints. As per Scrumguides.org (emphasis mine):
The Sprint Retrospective is an opportunity for the Scrum Team to inspect itself...
So that includes the Product Owner.
Following the advice from Agile Retrospectives by Derby/Larsen we're trying to focus our meeting on one specific topic. We have iterations of one week, so we usually cover only one topic each week.
Now, at least half of our Retrospectives will be very tech-oriented: talking about how to spread technical knowledge between us and other teams, improving automated testing, trying new tools, et cetera.
Our Product Owner is not very technical at all, and will not be able to contribute all too much in this kind of Retrospective.
Any suggestions on how to deal with this? Do we do those Retrospectives with just the development team? Do we "need" to look for ways to include the Product Owner too?