Guitar Rig4.0.8をService Centerから更新ファイルのダウンロードができます。
以下メールで送られてきたアップデート内容。

Main new and improved features:
– New amp Cool Plex (Guitar Rig 4 Pro only)
– New Master FX section
– Added expert panel with assigned parameters to all Modifiers
– Added Save buttons to the toolbar above the rack
– Added preset selection to component save drop down menu
– Improved Tuner algorithm
– Improved Metronome tap tempo
– Reduced Loopmachine memory footprint and improved cache prefetching (Guitar Rig 4 Pro only)
– Revised component Hotswap mode usage
– GUI update for several components
– Extended automation parameter list with 512 parameters
– Added static automation IDs to standard Rack Tools
– Added automation IDs for Input Gain, Gate, Master Volume, Limiter
– Added Bright mode to Citrus expert panel (Guitar Rig 4 Pro & Essential only)
– Added SHIFT selection of components in rack
– Improved drag and drop of components in rack
– Presets jumps can be assigned by dragging a preset on a RK button
– Added translated manuals in Japanese, French, Spanish and German
– Added manual addendum
– Support for Kore 2.1.1
– Added Kore user page to all factory presets
とりあえず起動してみて気づけた点。
・アンプが１個増えている。
・ギターリグ3時代に作ってDeleteすると固まっていた古い音色を普通に消せるようになった。