rake db:rollback　でDEPRECATION WARNING: Sprockets

夏ぐらいに開発していたRuby on Railsのプログラムを久々に修正・追加開発をしていたところ、Migrationを追加して、rake db:migrate をしたところ、下記のようなWarningが出てきました。

DEPRECATION WARNING: Sprockets method `register_engine` is deprecated.
Please register a mime type using `register_mime_type` then
use `register_compressor` or `register_transformer`.
https://github.com/rails/sprockets/blob/master/guides/extending_sprockets.md#supporting-all-versions-of-sprockets-in-processors
 (called from block in <class:Railtie> at /usr/local/rvm/gems/ruby-2.3.0/gems/less-rails-2.8.0/lib/less/rails/railtie.rb:16)
DEPRECATION WARNING: You are using the a deprecated processor interface Less::Rails::ImportProcessor.
Please update your processor interface:
https://github.com/rails/sprockets/blob/master/guides/extending_sprockets.md#supporting-all-versions-of-sprockets-in-processors
 (called from block in <class:Railtie> at /usr/local/rvm/gems/ruby-2.3.0/gems/less-rails-2.8.0/lib/less/rails/railtie.rb:21)

いろいろと調べると、どうもgemファイルの方かなということで、
他の質問でもあったとおり（ https://teratail.com/questions/43607 ）
gem sass-rails を5.0.6にUpdateしてみましたが、エラーがまだ消えません。

なお、Gem fileは下記のとおりです。

source 'https://rubygems.org'


# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails'
# Use sqlite3 as the database for Active Record
#gem 'sqlite3'
gem 'mysql2', '~> 0.3.20'

# Use SCSS for stylesheets
gem 'sass-rails', '~> 5.0.6'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# Use CoffeeScript for .coffee assets and views
gem 'coffee-rails', '~> 4.1.0'
# See https://github.com/rails/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby

# Use jquery as the JavaScript library
gem 'jquery-rails'
# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.0'
# bundle exec rake doc:rails generates the API under doc/api.
gem 'sdoc', '~> 0.4.0', group: :doc


# Use ActiveModel has_secure_password
gem 'bcrypt', '~> 3.1.7'

# Use Unicorn as the app server
# gem 'unicorn'

# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development

gem 'seed-fu', '~>2.3'
gem 'rails-i18n'
gem 'jquery-turbolinks'
gem 'therubyracer' 
gem 'less-rails' 
gem 'twitter-bootstrap-rails'
gem 'kaminari' 
gem 'bootstrap-sass'
gem 'pry-byebug', group: :development
gem 'ransack'
gem 'active_attr'


gem 'wicked'
gem 'enum_help'


gem 'order_as_specified'

gem 'autoprefixer-rails'

また、rubyおよびrailsのバージョンは下記です。
ruby 2.3.0p0 (2015-12-25 revision 53290) [x86_64-linux]
Rails 4.2.7.1

なお、これは直接同じ事が原因かわからないのですが、bundle db:install はWarningメッセージがでても進むのですが、bundle db:rollbackはどうもワーニングメッセージだけで処理をしてくれません。

よろしくお願いいたします