diff --git a/openapi/CHANGELOG.md b/openapi/CHANGELOG.md
new file mode 100644
index 00000000..7dc74883
--- /dev/null
+++ b/openapi/CHANGELOG.md
@@ -0,0 +1,129 @@
+# AdGuard Home API Change Log
+
+
+## v0.99: incompatible API changes
+
+* A note about web user authentication
+* Set filtering parameters: POST /control/filtering/config
+* Set filter parameters: POST /control/filtering/set_url
+* Set querylog parameters: POST /control/querylog_config
+* Get statistics data: GET /control/stats
+
+
+### A note about web user authentication
+
+If AdGuard Home's web user is password-protected, a web client must use authentication mechanism when sending requests to server.  Basic access authentication is the most simple method - a client must pass `Authorization` HTTP header along with all requests:
+
+	Authorization: Basic BASE64_DATA
+
+where BASE64_DATA is base64-encoded data for `username:password` string.
+
+
+### Set filtering parameters: POST /control/filtering/config
+
+Replaces these API methods:
+
+	POST /control/filtering/enable
+	POST /control/filtering/disable
+
+Request:
+
+	POST /control/filtering_config
+
+	{
+		"enabled": true | false
+		"interval": 0 | 1 | 12 | 1*24 | 3*24 | 7*24
+	}
+
+Response:
+
+	200 OK
+
+
+### Set filter parameters: POST /control/filtering/set_url
+
+Replaces these API methods:
+
+	POST /control/filtering/enable_url
+	POST /control/filtering/disable_url
+
+Request:
+
+	POST /control/filtering/set_url
+
+	{
+		"url": "..."
+		"enabled": true | false
+	}
+
+Response:
+
+	200 OK
+
+
+### Set querylog parameters: POST /control/querylog_config
+
+Replaces these API methods:
+
+	POST /querylog_enable
+	POST /querylog_disable
+
+Request:
+
+	POST /control/querylog_config
+
+	{
+		"enabled": true | false
+		"interval": 1 | 7 | 30 | 90
+	}
+
+Response:
+
+	200 OK
+
+
+### Get statistics data: GET /control/stats
+
+Replaces these API methods:
+
+	GET /control/stats_top
+	GET /control/stats_history
+
+Request:
+
+	GET /control/stats
+
+Response:
+
+	200 OK
+
+	{
+		time_units: hours | days
+
+		// total counters:
+		num_dns_queries: 123
+		num_blocked_filtering: 123
+		num_replaced_safebrowsing: 123
+		num_replaced_safesearch: 123
+		num_replaced_parental: 123
+		avg_processing_time: 123.123
+
+		// per time unit counters
+		dns_queries: [123, ...]
+		blocked_filtering: [123, ...]
+		replaced_parental: [123, ...]
+		replaced_safebrowsing: [123, ...]
+
+		top_queried_domains: [
+			{host: 123},
+			...
+		]
+		top_blocked_domains: [
+			{host: 123},
+			...
+		]
+		top_clients: [
+			{IP: 123},
+			...
+		]
+	}