Clearification of supported Neo4j versions

Added info to README and more informative error message.

README.md

@@ -50,6 +50,14 @@ for result.Next() {
 return result.Err()
 ```
 
+## Neo4j and Bolt protocol versions
+
+The driver implements Bolt protocol version 3. This means that either Neo4j server 3.5 or above can be used with the driver.
+
+Neo4j server 4 supports both Bolt protocol version 3 and version 4.
+
+There will be an updated driver version that supports Bolt protocol version 4 to make use of new features introduced there.
+
 ## Connecting to a causal cluster
 
 You just need to use `bolt+routing` as the URL scheme and set host of the URL to one of your core members of the cluster.

neo4j/internal/bolt/connect.go

@@ -71,7 +71,7 @@ func Connect(serverName string, conn net.Conn, auth map[string]interface{}, log
 		}
 		return boltConn, nil
 	case 0:
-		err = errors.New("Server did not accept any version")
+		err = errors.New("Server did not accept any of the requested Bolt protocol versions. Only Neo4j version 3.5 and version 4 currently supports Bolt protocol version 3")
 	default:
 		err = errors.New(fmt.Sprintf("Server responded with unsupported version %d", ver))
 	}