Update README.md

Add renew_from_now and renew_expired.

README.md

@@ -341,10 +341,12 @@ lsd_notify_auth:
 - `register`: boolean; if `true`, registering a device is possible; `true` by default.  
 - `renew`: boolean; if `true`, loan extensions are possible; `false` by default. 
 - `return`: boolean; if `true`, early returns are possible; `false` by default. 
-- `renting_days`: maximum number of days allowed for a loan. The maximum end date of a license is based on the date the loan starts, plus this value. No loan extension is possible after this upper limit. Use a large value (20000?) if you operate a subscription model.  
-- `renew_days`: default number of additional days for a loan extension. It will be overwritten by an explicit attribute of the renew command. 
-- `renew_page_url`: URL template; if set, the renew feature is implemented as an HTML page. This url template supports a `{license_id}`, `{/license_id}` or `{?license_id}` parameter. The final url will be inserted in the 'renew' link of every status document.
-- `renew_custom_url`: URL template; if set, the renew feature is managed by the license provider. This url template supports a `{license_id}`, `{/license_id}` or `{?license_id}` parameter. The final url will be inserted in the 'renew' link of every status document.
+- `renting_days`: maximum number of days allowed for a loan. The maximum license end date is based on the date the loan starts, plus this value. No loan extension is possible after this upper limit. Use a large value (20000?) if you operate a subscription model.  
+- `renew_days`: default number of additional days for a loan extension. An explicit attribute of the renew command will overwrite it. 
+- `renew_from_now`: boolean; if `true`, the number of days of an extension is based on the current timestamp, not the license end date. 
+- `renew_expired`: boolean; if `true`, the license provider allows the extension of an expired license. 
+- `renew_page_url`: URL template; if set, the renew feature is implemented as an HTML page. This url template supports a `{license_id}`, `{/license_id}` or `{?license_id}` parameter. The final url will be inserted in every status document's 'renew' link.
+- `renew_custom_url`: URL template; if set, the license provider manages the renew feature. This url template supports a `{license_id}`, `{/license_id}` or `{?license_id}` parameter. The final url will be inserted in the 'renew' link of every status document.
 
 Detailed explanations about the use of `renew_page_url` and `renew_custom_url` are found in a [specific section of the wiki](https://github.com/readium/readium-lcp-server/wiki/Integrating-the-LCP-server-into-a-distribution-platform#option-manage-renew-requests-using-your-own-rules).