Bluetooth®︎ low energy in general 

Bluetooth® LE roles – connection based

Peripheral

• Offers connections and services
• Defines the security level of its services and data
• Acts as slave
• Example: Most applications, Door control,Service interface, Light, Roller Shutter, Heart rate monitor

Central

• Initiator for all connections with peripherals
• Always as master in a connection with a peripheral
• Example: mobile phone at service interface, remote controller

Bluetooth® LE roles – connection less

Broadcaster

• Only transmits advertising events
• Example: Sensor beacon

Obeserver

• Only recieves advertising events
• Example: Beacon receiver

Bluetooth® LE 4.0

• First version of Bluetooth® LE
• Low energy as protocol stack specified
• 31 Bytes per radio data packet ( low throughput)
• Output power lower than 10 mW (10 dBm)

Bluetooth® LE 4.2

• (Optional) Data length extension (DLE) to support
• packets up to 255 Bytes ( higher throughput)
• (Optional) Additional secure pairing modes
• (Low Energy Secure Connections - LESC)

Bluetooth® LE 4.1

• Better coexistence with 4G radio
• Optimisation of Bluetooth® LE behaviour through configurability of parameters (time interval for reconnection)
• Central and peripheral functions in one device
• New profiles, like IPSP (Internet Protocol Support Profile) for IPv6

Bluetooth® LE 5.0

• (Optional) Large advertising packets
• (Optional) New frequency hopping sequence for better coexistence
• (Optional) Increased maximum output power to 100 mW for higher range
• (Optional) 2 MBit/s phy data rate
• (Optional) Higher range due to LE Coded radio (Long Range mode)

--> All versions are downwards compatible.

Bluetooth® LE 5.1

• (Optional) Faster connection setup by GATT caching to save the discovery step
• (Optional) Advertising enhancements
• (Optional) Bluetooth® direction finding to detect the direction of a radio signal:
  • Angle of arrival (AoA) for item finding applications
  • Angle of departure (AoD) for indoor positioning applications

Bluetooth® LE 5.2

• (Optional) Enhanced Attribute Protocol Sharing radio sources of different profiles in one data packet
• (Optional) Adaptive power control to save power and reduce interference Monitor the RSSI and request the transmitter to reduce/increase its power
• (Optional) LE Isochronous Channels: allows the communication of time-bound data to one or more devices for time-synchronized processing discard data of radio packet after time to live (TTL)
• (Optional) New audio profiles (LE Audio)

Bluetooth® LE 5.2 Audio

• Multistream
  • Independent, synchronous streams
  • More robust and better stereo
• New applications
  • Connect hearing aid to PC, smart phone or TV
  • Broadcast audio sharing, e.g. for cinemas, theaters, airports,…
• Higher quality and less power consumption

Bluetooth® LE 5.3

• (Optional) Periodic Advertising Enhancement
  • Twice detected advertising packets are dropped during reception to save current
• (Optional) Connection Subrating
  • In periods with low traffic a connection may be slowed down temporarily to save current
• (Optional) Channel Classification Enhancement
  • Now the peripheral can also provide a black list of noisy radio channels

If you want to read more find here the whole Product Guide.