Facing issues in upgrading rails version -

when run bundle install shows :

fetching gem metadata https://rubygems.org/........ fetching additional metadata https://rubygems.org/.. resolving dependencies... have requested:   rails = 4.2.1  bundle has rails locked @ 4.1.0. try running `bundle update rails` 

then run: bundle update rails gives:

fetching gem metadata https://rubygems.org/........ fetching additional metadata https://rubygems.org/.. resolving dependencies... bundler not find compatible versions gem "railties":   in gemfile:     devise (>= 0) ruby depends on       responders (>= 0) ruby depends on         railties (< 4.2, >= 3.2) ruby      rails (= 4.2.1) ruby depends on       railties (4.2.1) 

please me out in solving this. in advance.

it looks using older version of devise--you'll need update devise version work rails 4.2 (bundle update devise). once devise updated 3.4.x, can use railties v4.2.1.