"macOS Big Sur 11.5.1 provides important security updates and is recommended for all users."

A M1 Mini owner running Big Sur 11.5 said software update listed the 11.5.1 update as 2.2GB, but the actual 11.5.1 update download was 3.11GB. She installed both 11.5 and 11.5.1 updates in Safe Mode. (M1 Mini firmware version still 6723.140.2.)

You can check Apple's Big Sur forum for feedback. (Posts may be in previous problem threads.)
And for M1 owners, also check the Mac Mini, iMac, MacBook Pro, & MacBook Air forums.
 

• iOS 14.7.1 release notes
  - "fixes an issue where iPhone models with Touch ID cannot unlock a paired Apple Watch using the Unlock with iPhone feature. This update also provides important security updates and is recommended for all users."
• iPadOS 14.7.1 release notes
  - "provides important security updates and is recommended for all users."
• About the security content of iOS 14.7.1 and iPadOS 14.7.1
  (Like Big Sur 11.5.1, this vulnerability is reportedly being actively exploited.)
  
  
• watchOS 7.6.1 release notes
  - "This update provides important security updates and is recommended for all users".
• About the security content of watchOS 7.6.1
  (The same fix as in macOS 11.5.1 & iOS/iPadOS 14.7.1 updates.)
  
  

• GarageBand amps up music creation with all-new Sound Packs from Dua Lipa, Lady Gaga, & today's top music producers (packs are free downloads for iOS/iPadOS)

  "All-new Remix Sessions and Producer Packs are available today as a free download from the Sound Library in GarageBand 2.3.11, the latest version of the app, for iOS and iPadOS. For more information, visit apple.com/ios/garageband."

  
  
• Apple Reports Third Quarter Results (press release)
  - Revenue up 36 percent to new June quarter record.
  - Services revenue reaches new all-time high.

• Check VPN (Virtual Private Network) and third-party software to help resolve network connectivity issues
  
  
• If you get a personalization error when reinstalling macOS on your Apple M1 chip Mac
  
  
• How to Reset the SMC (System Management Controller) of your Mac (Intel-based Macs)
  
  
• If you can't send or receive messages on iPhone, iPad, or iPod touch
  
  
• How to check the storage on your iPhone, iPad, and iPod touch
  
  
• How to clean your Apple products

• Freeware VM VirtualBox 6.1.26 update.
  - See Change Log for list of fixes & improvements.
  
  
• LG B6 OLED TV & UH6330/7650/7700 LCD TVs Firmware Update 05.60.20
  - Info and firmware download page. (Also added to firmware updates listing.)
  
  
• 2021 LG C1/G1/R1 OLED TVs Firmware Update 03.15.36
  - post includes update info and download pages.