New puzzles in the Challenge Trail

The free puzzles in the Challenge Trail have been updated in version 1.64.0:

• Most of the puzzles in the harder levels have been replaced with new puzzles that reflect the difficulty ratings more accurately.
• In the easier levels, some 4x4 puzzles are now featured.
• In total, there are more puzzles to play than before.

Other changes in this version:

• When the puzzle generator is configured with different weights for the different categories of puzzle difficulty, the puzzles are now generated with a better mix of difficulties.
• When a square has no candidate values left, a yellow warning symbol is shown, instead of a plain empty square. When this happens, it usually means there is a mistake somewhere. A quick way to fix mistakes is to use the built-in help.

The new symbol that is shown when there are no candidate values left can be seen in the screenshot below: