Kali repos contain 1.5.3; which is 3 releases old now.

https://www.bettercap.org/changelog/

v1.5.6 ( 2016-07-15 )

New Features

Fixes 0000252: new TeamViewer sniffer module.

Fixes

Fixes 0000256: Bumped colorize version to 0.8
Fixes 0000241: Exception due to invalid byte sequence in utf-8 when bettercap logger is trying to write to log file.
Fixed Formatting
Fixes 0000235 : HTTPS proxy unable to ignore invalid server certificate.
Make sure Kali is updated before installing Bettercap
Included correct install instructions for Bettercap on Kali.
Use sub! with block to avoid strange sub! behaviour when data contains the sequence backslash-backtick
Adding proper timeouts while fetching HTTPS certificates.

Code Style

Rescue syntax for udp_socket.rb
Refactor equals? at target.rb
Rescue syntax for packet_queue.rb
Line fold and rescue syntax in httpd.rb
Simplify if statements for teamviewer.rb
Simplify if statements for dhcp.rb
Rescue syntax on firewalls/bsd.rb
Formatting
Doc update