Add strategy-migration doc page

docs/deprecated.md

@@ -48,17 +48,12 @@ Please switch to the new [Parametrized Strategies](hyperopt.md) to benefit from
 
 // TODO-lev: update version here
 
-## Strategy changes
+## Strategy changes between V2 and V3
 
-As strategies now have to support multiple different signal types, some things had to change.
+We have put a great effort into keeping compatibility with existing strategies, so if you just want to continue using freqtrade in spot markets, there are no changes necessary.
+While we may drop support for the current interface sometime in the future, we will announce this separately and have an appropriate transition period.
 
-Dataframe columns:
-
-* `buy` -> `enter_long`
-* `sell` -> `exit_long`
-* `buy_tag` -> `enter_tag`
-
-New columns are `enter_short` and `exit_short`, which will initiate short trades (requires additional configuration!)
+Please follow the [Strategy migration](strategy_migration.md) guide to migrate your strategy to the new format to start using the new functionalities.
 
 ### webhooks - `buy_tag` has been renamed to `enter_tag`
 

docs/strategy_migration.md

@@ -0,0 +1,26 @@
+# Strategy Migration between V2 and V3
+
+We have put a great effort into keeping compatibility with existing strategies, so if you just want to continue using freqtrade in spot markets, there should be no changes necessary for now.
+
+To support new markets and trade-types (namely short trades / trades with leverage), some things had to change in the interface.
+If you intend on using markets other than spot markets, please migrate your strategy to the new format.
+
+## Quick summary / checklist
+
+* Dataframe columns:
+  * `buy` -> `enter_long`
+  * `sell` -> `exit_long`
+  * `buy_tag` -> `enter_tag` (used for both long and short trades)
+  * New column `enter_short` and corresponding new column `exit_short`
+* trade-object now has the following new properties: `is_short`, `enter_side`, `exit_side` and `trade_direction`.
+* New `side` argument to callbacks without trade object
+  * `custom_stake_amount`
+  * `confirm_trade_entry`
+* Renamed `trade.nr_of_successful_buys` to `trade.nr_of_successful_entries`.
+* Introduced new `leverage` callback
+* `@informative` decorator now takes an optional `candle_type` argument
+* helper methods `stoploss_from_open` and `stoploss_from_absolute` now take `is_short` as additional argument.
+
+## Extensive explanation
+
+

mkdocs.yml

@@ -23,6 +23,7 @@ nav:
     - Backtesting: backtesting.md
     - Hyperopt: hyperopt.md
     - Leverage: leverage.md
+    - Strategy migration: strategy_migration.md
     - Utility Sub-commands: utils.md
     - Plotting: plotting.md
     - Exchange-specific Notes: exchanges.md