devise-i18n | Translations for the devise gem | Translation library

First, as ThorTL67 noted in the comments, it is a good idea to update your Rails version incrementally, not in one big leap. That way, your dependency issues will be less complex.

Check what version of Bundler you are using by running bundle version. If that version is old, it might be that some dependencies are not correctly calculated, and it might help to update Bundler (gem update bundler).

Then to the steps you can take to update from 4.2 to 'some higher version'. The list of errors that you got shows the conflicts between gem dependencies. You can try and tackle these conflicts one by one.

It sounds like you've already got the "look for a blocking dependency, then fix it" cycle under control.

The one that currently needs attention is at the very bottom:

Today I had the same problem with one of our apps. We were using rails-assets-tether gem from https://rails-assets.org. We notice that the same gem is available in the main repository (https://rubygems.org). The solution was to remove source block from the Gemfile.

I think that if you need those gems, then you have to wait for the certificate to be renewed (by website owners) or find an alternative source of those gems.

Update:

You can replace https://rails-assets.org with http://insecure.rails-assets.org. Please remember to switch back to https endpoint after this issue has been fixed

I think you need to use font-awesome gem. I had the same issue before.

Rails admin uses an old version of fontawesome. Download the zip file here: http://fortawesome.github.io/Font-Awesome/3.2.1/assets/font-awesome.zip

Then put the following files into the /public/assets directory of your rails project, from the /font directory in the zip file:

As explained in the following answer

Bootstrap create that navbar collapse effect with media queries

CSS3 allows media dependent style-sheet by media (viewport?) and detect things such as width/height

More reading on media query at the following link:

Now you can go and test/check the css and @media queries performed in the following navbar example

You can see that the navbar has two main componenents, those that will always be displayed:

I would guess you have bad/unexpected order data in production. Review the data directly in MySQL, visit the view pages for each of the orders. Post here the orders index definition if practical.

Rails does come with I18n support by default, but it doesn't actually translate anything to other languages. That's what the rails-18n gem does. It adds translation files for

Available locales are:

af, ar, az, be, bg, bn, bs, ca, cs, cy, da, de, de-AT, de-CH, de-DE, el, el-CY, en, en-AU, en-CA, en-GB, en-IE, en-IN, en-NZ, en-US, en-ZA, en-CY,eo, es, es-419, es-AR, es-CL, es-CO, es-CR, es-EC, es-ES, es-MX, es-NI, es-PA, es-PE, es-US, es-VE, et, eu, fa, fi, fr, fr-CA, fr-CH, fr-FR, gl, he, hi, hi-IN, hr, hu, id, is, it, it-CH, ja, ka, km, kn, ko, lb, lo, lt, lv, mk, ml, mn, mr-IN, ms, nb, ne, nl, nn, or, pa, pl, pt, pt-BR, rm, ro, ru, sk, sl, sq, sr, sw, ta, th, tl, tr, tt, ug, ur, uz, vi, wo, zh-CN, zh-HK, zh-TW, zh-YUE

Complete locales are:

af, da, de, de-AT, de-CH, de-DE, en-US, es, es-419, es-AR, es-CL, es-CO, es-CR, es-EC, es-ES, es-MX, es-NI, es-PA, es-PE, es-US, es-VE, et, fa, fr, fr-CA, fr-CH, fr-FR, id, ja, ka, ml, nb, nl, nn, pt-BR, sv, sv-SE, tr, zh-CN, zh-HK, zh-TW, zh-YUE, uk

so you can drop in those files and have a decent starting point for rails' baked in strings. (Take a look at any of the any of the locale files to see what translations you end up getting).

For the devise-i18n, per the gem's README:

Devise supports i18n in controllers, models, and in other areas, but it does not have support for internationalized views. devise-i18n adds this support. Devise also does not include the actual translations. devise-i18n does this too.

Devise is a gem written independently for use with Ruby on Rails, and the author didn't add support for I18n into the views. This gem, then, overrides the views supplied by Devise in order to add in I18n support, as well as supply translation files for a ton of different locales (skimming through, looks like roughly the same list as the rails-i18n gem)