What does BR stand for?
BR stands for "Battle Rating". Battle rating is a number that generally shows how strong a player is, especially when compared to other players'. Each game provides a different value for each stat, although the BR-per-stat is generally similar across all games.
Any stat or item that adds battle prowess will affect a player's BR. There are a few rare exceptions that may not be calculated into a player's BR, usually having to do with % chances to positively affect a player's character or negatively affect enemy characters.
BR is not necessarily a marker for how strong one is. This is a general number that calculates a player's stats and additional battle prowess and provides a generic number. A player may have a high BR, but if they have non-optimal stats for a their class, they may have a "false BR". It is entirely possible for a lower BR player to beat a higher BR player if their stats are more desirable for their class and strategy.
What would make BR change?
If a player changes anything that affects their character, this will affect their BR positively or negatively. This can be done through upgrading skills, equipment, pets, leveling, and so many other factors. Please refer to specific game guides for more detailed information in changing a player's character BR.
What if BR is changing due to a game change?
These should be explained in game guides, official support channels, and/or in the forums. Sometimes BR value for each stat may be reworked slightly, providing a higher or lower BR. Not to worry! If a player's BR has been altered slightly, their stats and overall fighting ability haven't changed in the least. BR is a generic number and should not be the final conclusion when determining a player's strength.
What if BR is changing due to a bug?
A BR change is almost always attributed to overlooking a difference in equipped items/heroes/gems/etc. If a player's BR has changed, the first thing they should check is everything accompanying their character: check gems, gear, pets, troops, special boosts, and any other factor that affects stats/BR.
After a player has ensured nothing is out of the ordinary, check actual stats. Is there a large decrease in a single stat? Is there a large increase in a less-desirable stat? Checking these factors for 2-3 consecutive days, ensuring everything is consistent, will help weed out and doubt that there is an issue.
If a player's stats and BR have changed dramatically, we ask for documentation of the changes over a couple days, ensuring everything is the same from day-to-day. This means documenting the rise and fall of stats and BR, along with other game factors that could affect them.