Table 4.

Themes, subthemes, and illustrative quotes (acceptability and usability of the iCare app).

Themes and subthemes		Quotes
1. When you are not used to these things, they take time to get the hang of
	Limited proficiency in the use of modern technology	“I don’t use mobile phones very often, only for rings.” [think aloud; P104] “I don’t really do apps...I just use the phone to check my, have I got a text message.” [think aloud; P108] “I don’t often use [the phone] as a web, for webbing.” [think aloud; P114] “I’m not very digitally minded...literally, I brought my iPhone to take pictures.” [think aloud; P105]
	Learning over time	“I went to school in the 70s and university in the 80s, so this is not my kind of thing but I could adopt it, I could try.” [think aloud; P116] “The more I use it, I’ll get the hand of it better.” [think aloud; P101] “Many people love technology, I love it, I’m crap at it but I want to try and learn.” [think aloud; P110] “I find it okay because I’ve got used to it now. I’ve looked at it a few times and then I get used to it.” [week 2; P114] “It seems pretty easy to navigate once you know how it works...Once you learn how to use it, it’s pretty intuitive.” [week 6; P117]
	Small font size	“I have to wear glasses to read and I get tired eyes, watery. I think the writing is, should be a bit bolder.” [think aloud; P108] “I think I have already said it before, I think the wording needs to be a bit bigger and bolder.” [week 2; P109]
2. It’s not fun, but it is informative
	Creating an experience beyond the content itself	“I think perhaps you could consider other things like linking it to other systems. For example, like Patient Access...It’s like a GP [general practitioner] practice app where patients can log in, book appointments, repeat prescriptions and things like that. Perhaps you could link it to that because on there, there’s information and support for carers as well.” [think aloud; P106] “There’s nothing about connecting with...other carers. Nothing about having a discussion about something that you’ve just seen...You could gamify this, that would be more fun...because we spend the entire time reading which is, I get fed up with...being told ‘read this’...I don’t have the time, the energy or the capacity.” [think aloud; P121] “I suppose they are trying to make it a little bit more interesting, but they could have just done it as bullet points.” [think aloud; P104] “Because it is not a game. I don’t see [the point] of an extra click. And it makes me feel like I am doing an exam, a multiple-choice exam and it doesn’t make me feel like this is something [I’m going to want to do], I think I would get bored of it.” [think aloud; P111]
	Customization and more personalized content	“I think it would be useful to have some favorites, so sections that you know you’d want to go back to more easily.” [think aloud; P106] “There isn’t any [customization]. It’s led by the app. It’s just a whole bunch of lines. I can’t customize anything... There isn’t anything that says, I’ve done this bit, and these are the bits that are next.” [think aloud; P121] “I don’t need that [information] at the moment but if it [was] relevant to my situation... What do they call them now... flow chart! Now that would be useful...so you’re going down a tree until you hit the specific point that you are looking for...I think you have to try and tailor these things.” [think aloud; P113]
	Good use of videos	“I quite like the video content...You don’t want to just read loads and loads and loads of information.” [think aloud; P106] “I like the way she is talking...a good pace and she was very clear in describing what to look out for...the language she used – it wasn’t really hard terminology.” [think aloud; P107]
	Information is short and to the point	“Everything seems just short and to the point to keep me engaged because, especially as the care you just, your concentration level is just, you’ve just got to be on it, you’re doing other things and also tired...I just need something to spark a little something in me and be simple.” [think aloud; P121] “It’s not really a fun topic, but it’s very interesting...It was just concise information that someone in my position would need to know, it wasn’t [over the top] with lots of unnecessary information. It was just enough so that I know what to look for and what to do.” [week 2; P118] “I think it’s very quick and straight to the point most of the time...it’s a very good introduction.” [week 6; P119]