- Improved overall performance. ...

- Hid the IXLStylized interface (this was long overdue).
- Fixed Issue #6084

- Added Excel Tables, and you can call a cell using the field name. ...

- Modified the behavior of range.InsertRows/Columns. When you insert a column after the range or a row below the range, the range will be expanded to include the newly added rows/columns. If you insert a column before the range or a row above the range, the range will move accordingly but not expand. This is the default behavior but the insert rows/columns now have a parameter for you to specify whether or not to expand the range.
- Added range.ClearStyles() method. It will preserve number/date formats though.
- Added  set only properties to .Cells(...) so now you can do something like: worksheet.Row(1).Cells("1-3,5,7").Value = "Good!";
- Added methods to .Cells(...)
- Removed the properties range.FormulaA1 and range.FormulaR1C1. Please use range.Cells().FormulaA1 and range.Cells().FormulaR1C1 instead.
- Improved save performance, A LOT. (Thanks to GFraser for the help locating the bottlenecks). I still have a few things to do to improve the performance but I wanted to release this version because of the substantial improvements already made.

- AdjustToContents now ignores merged cells. ...

- Added overloads to AdjustToContents so you can specify the rows/columns you want to use for calculating the height/width
- Renamed range.ContainsRange(range) to range.Contains(range)
- Added ability to freeze panes via the worksheet.SheetView object
- Added method range.Intersects(range)

- Restructured Rows/Columns/Range/RangeRow/RangeColumn objects to be more natural. ...

- Commented the interfaces so now you'll get useful information from the intellisense.

- ClosedXML now supports Theme colors. ...

- Switched from using Color to XLColor.
- Added method worksheet.Clear()
- Fixed issues 5946, 5962

Fixed Issues: 5951, 5953, 5956, 5957, 5958

- Added ability to specify the order of the sheets via the worksheet.SheetIndex property. ...

- Fixed issues 5947, 5948, plus a problem with inserted sheets (special thanks to Marc Wimmer for these)

Improved performance (A LOT)

Replaced optional parameters with method overloads.

- We're now releasing for both .Net 3.5 and .Net 4.0 frameworks. ...

- Merge() and Unmerge() now return a range.
- Replaced range.CreateNamedRange with range.AddToNamed
- Made it easier to create, use, modify, and delete named ranges (including those pointing to multiple ranges). Please see modified examples.
- Fixed issue #5908

Fixed bug when opening/saving workbooks with hyperlinks

- Added cell.GetTimeSpan() method

- ClosedXML now opens any Excel '07/'10 file. If you have a file that doesn't open/save correctly, please submit a ticket ...

on the Issue Tracker tab and attach the file that you're trying to open.
- You can open/save workbooks from/to streams.
- Fixed issue #5844

ClosedXML now opens any Excel '07/'10 file. ...

I have a bunch of small enhancements I want to implement before release though.

Optimized loading

Fixed Issue # 5822 and made some small optimizations.

Fixed Issue # 5822

- Fixed issue 5821

- Added ability to set a cell's value to an IEnumerable and it will copy the collection's data into a table starting from the initial cell. ...

- Added ability to copy a range
- Added Named Ranges
- Renamed worksheets.GetWorksheet to worksheets.Worksheet (it feels more natural)

- Added Hide/Unhide methods to Row(s)/Column(s) ...

- Added outline functionality (grouping of rows and columns)
- Implemented formulas (A1 and R1C1 notations)
- Added property worksheet.CalculationMode (Auto, AutoNoTable, Manual, Default)
- Added property worksheet.ReferenceStyle (R1C1, A1, Default)

- Shifting/deleting a range that will affect a merged group of cells will break the merge. ...

- Using an variable of type IXLRange for a range that was completely deleted raises an error.
- Added the following methods: range.ContainsRange(String), cell.Clear(), cell.Delete(XLShiftDeletedCells)
- Added workbook properties (Author, Title, Subject, etc.)
- Renamed cell.GetFormattedValue() to cell.GetFormattedString()
- Added method "AdjustToContents" to the Row(s)/Column(s)

Implemented a more reliable way to transpose borders.

Added Transpose method to ranges. This method transposes data, styles, and merged cells accordingly.

- Changed the cell value property to be an Object. This allows for a more natural way of setting the values. ...

- Added methods to IXLCell which will hopefully result in less casting on your side.
- Removed the Load method from the XLWorkbook interface in favor of the existing contructor "XLWorkbook(String file)". Since you have to load the file before doing anything else, it doesn't make sense not to put it in the constructor.
- Added the following methods to ranges FirstCellUsed/LastCellUsed

Inserting rows/columns to worksheets/ranges will shift existing referenced ranges accordingly. ...

Added a DateFormat to the styles. It does the same function as Style.NumberFormat but it will be more intuitive for someone trying to format a date.
Added "IXLRanges Ranges(...)" methods to the IXLRange interface. IXLRanges is a collection of ranges which allow you to modify them all in one shot.
Worksheet.Style, Worksheet.Columns(), and Worksheet.Rows() now apply to the entire worksheet (not just the used cells).

Inserting rows/columns to worksheets/ranges will shift existing referenced ranges accordingly. ...

Added a DateFormat to the styles. It does the same function as Style.NumberFormat but it will be more intuitive for someone trying to format a date.
Added "IXLRanges Ranges(...)" methods to the IXLRange interface. IXLRanges is a collection of ranges which allow you to modify them all in one shot.
Worksheet.Style, Worksheet.Columns(), and Worksheet.Rows() now apply to the entire worksheet (not just the used cells).

Added the ability to load an Excel file created with ClosedXML. It *might* open a file created without ClosedXML but any features not recognized by ClosedXML will be lost.

Broken build. It's halfway through implementing a mechanism to load existing files (created with ClosedXML). Just wanted to safeguard these changes (yes, I'm that paranoid about loosing my work).`

Made it more intuitive to work with rows/columns/ranges. Please see the release notes.

Finally got working a more natural way to deal with collections of rows/columns/ranges ...

Old Method (You have to iterate through every item):
ws2.Columns("G:H").ForEach(c => c.Style.Fill.BackgroundColor = Color.Blue);

New Method (No iteration necessary, the program knows you want to apply the style/whatever to the entire collection):
ws2.Columns("G:H").Style.Fill.BackgroundColor = Color.Blue;

Right now it only works with columns but I'll add it to rows and ranges before release.