I agree in large measure with what @inResponse has said. I am a die hard Freestyle Libre person. It works really well with my body chemistry (when I compare it to a bloodstick test). I prefer it to the Dexcom, not least because I do not want to have to try to dispose of the significant additional product and packaging waste that the Dexcom product seems to generate.
That said, I assume in the United Kingdom that the official regulator of medical devices, the Medicines and Healthcare Regulatory Agency has authorised and licensed the Freestyle Libre 2 system on the basis that it will, when applied and used normally in accordance with the manufacturer's use instructions, provide in normal use low and/or high glucose alarms when the Libre 2 sensor is used with the Librelink app on a compatible mobile phone.
If it isn't doing so; if people are finding that because of either too many faulty Libre 2 sensors and/or the Librelink app isn't functioning normally because of updates; and you are finding that self-diagnosing or treating one's hypoglycaemia or hyperglycaemia is being delayed, then everyone using the product in the UK ought to give serious consideration about whether they should report their experiences using the MHRA's Yellow Card incident.
This past week I had four (4) Libre 2 sensors - one after the other - fail to provide high and low glucose alarms on my Freestyle Libre 2 Reader over 96 hours. Yes, perhaps I was unlucky and received a batch of sensors that were not functioning as they should. However, that level of failure shouldn't be acceptable. Ever.
At the moment I cannot use the Freestyle Librelink app on my smartphone to get high and low glucose alarms following updates to the Librelink app without doing lots of additional things (including uninstalling and reinstalling Librelink) and switching my phone on and off. Even then this only fixes not receiving alarms temporarily. There's a limit to how often I am prepared to do that. Abbott need to fix the issue.
I'm aware updates Abbott made to the Librelink app coincide with my mobile's operating system being updated by the manufacturer of my mobile. But I've paid for my mobile on the basis it will receive period updates. Those updates make my phone more stable and less prone to be hacked.
And I'm not prepared to use third party apps, none of which have been submitted to an official, government-backed, medical devices regulator and scrutinised, authorised and licensed by that regulator as clinically safe and fit for purpose, nor third party apps which have not been authorised officially by the manufacturer of the Freestyle Libre system.
I have already read elsewhere more than one account from others who say they relied on the Librelink app to give an alarm when their glucose was going low so they could double check before it went too low and had a fighting chance to do something about it. Following software updates they received no low alarms. In one instance someone said they woke up to paramedics treating them for severe hypoglycaemia (with all the implications that has for keeping one's driver's licence IF one drives a car in the UK).
The MHRA is there to ensure medical devices (which includes sensors and computer software) UK patients use are safe and work for patients as they are supposed to work in accordance with the licence the MHRA has given the manufacturer. UK diabetics shouldn't be timid in reporting concerns to the MHRA. The MHRA is there to try and keep us safe.