I downgladed ruby-gtk2, ruby-glib2, ruby-atk and ruby-gdk-pixbuf2 to 2.2.5-3+b2. But it still doesn't start.
$ mikutter Traceback (most recent call last): 48: from /usr/share/mikutter/mikutter.rb:42:in `<main>' 47: from /usr/share/mikutter/core/miquire.rb:18:in `miquire' 46: from /usr/share/mikutter/core/miquire.rb:75:in `miquire' 45: from /usr/share/mikutter/core/miquire.rb:75:in `each' 44: from /usr/share/mikutter/core/miquire.rb:76:in `block in miquire' 43: from /usr/share/mikutter/core/miquire.rb:95:in `file_or_directory_require' 42: from /usr/share/mikutter/core/miquire.rb:98:in `miquire_original_require' 41: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require' 40: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require' 39: from /usr/share/mikutter/core/boot/load_plugin.rb:10:in `<top (required)>' 38: from /usr/share/mikutter/core/miquire_plugin.rb:96:in `load_all' 37: from /usr/share/mikutter/core/miquire_plugin.rb:36:in `each_spec' 36: from /usr/share/mikutter/core/miquire_plugin.rb:33:in `each' 35: from /usr/share/mikutter/core/miquire_plugin.rb:33:in `each' 34: from /usr/share/mikutter/core/miquire_plugin.rb:38:in `block in each_spec' 33: from /usr/share/mikutter/core/miquire_plugin.rb:98:in `block in load_all' 32: from /usr/share/mikutter/core/miquire_plugin.rb:146:in `load' 31: from /usr/share/mikutter/core/utils.rb:278:in `atomic' 30: from /usr/lib/ruby/2.5.0/monitor.rb:226:in `mon_synchronize' 29: from /usr/share/mikutter/core/utils.rb:278:in `block in atomic' 28: from /usr/share/mikutter/core/miquire_plugin.rb:147:in `block in load' 27: from /usr/share/mikutter/core/miquire_plugin.rb:147:in `each' 26: from /usr/share/mikutter/core/miquire_plugin.rb:149:in `block (2 levels) in load' 25: from /usr/share/mikutter/core/miquire_plugin.rb:146:in `load' 24: from /usr/share/mikutter/core/utils.rb:278:in `atomic' 23: from /usr/lib/ruby/2.5.0/monitor.rb:226:in `mon_synchronize' 22: from /usr/share/mikutter/core/utils.rb:278:in `block in atomic' 21: from /usr/share/mikutter/core/miquire_plugin.rb:147:in `block in load' 20: from /usr/share/mikutter/core/miquire_plugin.rb:147:in `each' 19: from /usr/share/mikutter/core/miquire_plugin.rb:149:in `block (2 levels) in load' 18: from /usr/share/mikutter/core/miquire_plugin.rb:146:in `load' 17: from /usr/share/mikutter/core/utils.rb:278:in `atomic' 16: from /usr/lib/ruby/2.5.0/monitor.rb:226:in `mon_synchronize' 15: from /usr/share/mikutter/core/utils.rb:278:in `block in atomic' 14: from /usr/share/mikutter/core/miquire_plugin.rb:158:in `block in load' 13: from /usr/share/mikutter/core/miquire_plugin.rb:158:in `load' 12: from /usr/share/mikutter/core/plugin/gtk/gtk.rb:5:in `<top (required)>' 11: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require' 10: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require' 9: from /usr/lib/ruby/vendor_ruby/gtk2.rb:11:in `<top (required)>' 8: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require' 7: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require' 6: from /usr/lib/ruby/vendor_ruby/gtk2/base.rb:12:in `<top (required)>' 5: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require' 4: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require' 3: from /usr/lib/ruby/vendor_ruby/glib2.rb:101:in `<top (required)>' 2: from /usr/lib/ruby/vendor_ruby/glib2.rb:105:in `rescue in <top (required)>' 1: from /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require' /usr/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require': cannot load such file -- glib2.so (LoadError) -- 大島秀夫(Hideo Oshima) http://hidenosuke.org/