2.6.2:

New:
UI tweaks: sidebar icons, color and spacing.
Improved countries selector.

2.6.1:

Fix:
Crash on startup with database under certain conditions.

2.6:

New:
Sideview style UI.
Load most recently used database in offline mode.
Email support button.

Update:
Airports database update.

2.5.4:

New:
Added US WAC to web map sources.

2.5.3:

New:
Databases in store/map are sorted by name.
Option to no longer see outdated databases.

Fix:
Change text of buy button to "buy/restore" to make usage clearer for end users.
Clarify locale of US mapping options.

2.5.2:

New:
Quickload button in search pane for current destination airport.

Update:
Airports database update.

Fix:
Verification failure after purchase (result: no download) on older iOS devices.

2.5.1:

Fix startup hang/IAP purchases not working.

2.5.0:

New:
ZephyrCharts is now free.
ZephyrCharts World and ZephyrCharts Lite have been discontinued.
ZephyrCharts is now iOS 6 only.
In app purchases: downloadable maps.
Options: VFR, IFR Low/High, TAC, World, Continents.
Custom UI elements for search, airports, frequencies and runways.
Bearing/direction/distance in search/airport detail views.

2.2.1:

New:
Localizations: Italian, Japanese.
iOS6 Routing app support.
Icon Choices: Disable, Cursor (small).
Chinese translation improvements. (Thanks: Lingshuang Wu)

Updates:
Airports database update.

Fix: non-localized strings in iOS settings pane.

2.2.0:

New:
Localizations: Spanish, Chinese, French, German.
Support for iPhone 5, iOS6.

Updates:
Airports database update.
VFR, TAC, IFR High/Low enroute chart updates.

2.1.0:

New:
ZephyrCharts is now iOS5 only.
Improved airports city selector.
Great circle routes.
Improved settings pane.
Search honors countries settings preference.

2.0.2:

New:
ZephyrCharts World: Local maps, levels 1-10.

2.0.1:

New:
Airports/heliports only preference.
Improved search functionality/distance preferences.
Countries preference to select/limit number displayed.
More airplane icons.
About pane tweaks.

Updates:
Airports/data update.

2.0:

ZephyrCharts has gone international! 245 countries, 44000 airports!

New:
New airport info picker and dataset. Frequency/runway information.
Redesigned about pane.
Search preferences: by Ident or Name.

Removed:
ZephyrCharts longer displays approach plates.

1.x:

For historical release information look here.