Why the message arrived an hour after it was sent
When a message only appears after you unlock the phone, or a reminder from an app fires late, the app is rarely at fault. Android deliberately delays background work to save battery, and several phone makers add a second, more aggressive layer on top. Both can be told to leave a specific app alone. The skill is doing that for the three apps that matter rather than for everything.
What is actually happening
| Cause | What you notice | The fix |
|---|---|---|
| Android battery optimisation | Notifications arrive in a burst when you pick up the phone | Set the app's battery use to Unrestricted |
| The phone maker's sleep list | An app goes quiet a few days after you last opened it | Take it off the sleeping or deep sleeping list |
| Background data restricted | Messages arrive only on WiFi, or only when you open the app | Allow background data, and unrestricted data under Data Saver |
| A muted notification category | The notification arrives but makes no sound | Check the app's notification categories |
| Do Not Disturb or a bedtime mode | Everything is silent at certain hours | Check the schedule and its exceptions |
| No Google Play services on the phone | Some apps never notify while others are fine | Use apps that offer their own delivery method |
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The fix, in order
- Open the app's settings page Long press the app icon, then App info. Everything below lives on this page or one level down.
- Set battery use to Unrestricted On recent Android it sits under Battery or App battery usage, with a choice of Unrestricted, Optimised and Restricted. Unrestricted lets the app run while the phone is idle.
- Remove it from the maker's sleep list Samsung calls these sleeping and deep sleeping apps, in the battery settings, alongside a list of apps that never sleep. Xiaomi phones have an Autostart switch. Other brands use other names.
- Allow background data Under Mobile data on the same page. If Data Saver is on, give the app unrestricted data as well.
- Test with the screen off Lock the phone, leave it for half an hour, and ask someone to send a message. A test on a phone in your hand proves nothing.
Why some phones are worse than others
Standard Android delays background work but lets high priority messages through. Several manufacturers go further and close apps that have not been opened recently, whatever they are waiting for, and the settings that stop it are named differently on every brand and often every version. The first app below measures how aggressive your particular phone is and points to the settings for your model.
Runs a benchmark showing how aggressively your phone stops background work, and explains the settings to change for your brand. Start here.
Sends a test notification through Google's push service, which tells you whether a delay comes from the phone or from the app.
Records every notification with the time it arrived, for phones whose built in history is missing or hard to find.
The same idea with search and categories, useful for spotting which apps are the ones arriving late.
Notifications from your own scripts or server. It can keep its own connection instead of relying on Google's service, at some cost in battery.
Exempt a few apps, not all of them
- Messaging apps you rely on
- An alarm or medication reminder app
- Apps that approve sign-ins by notification
- A health or safety app that must alert you
- Games
- Shopping and social feeds
- Anything that mostly sends promotions
- Apps you are not sure you still use
Check the history, set the app to Unrestricted, take it off the sleep list, allow background data, then test with the screen off. Three apps, not thirty.
Frequently asked questions
Will exempting apps flatten the battery?
A few messaging and alarm apps make little difference, because they spend nearly all their time waiting. Exempting everything is what costs battery, and it defeats the point of the feature.
Why did it work until a system update?
Major updates can reset battery settings or add a new layer of optimisation. After any big update, check the few apps you exempted.
Does locking an app in the recent apps view help?
On some phones, yes: several manufacturers let you lock an app there so it is not cleared. On others it does nothing, and it is no substitute for the battery settings.
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