Update requirements in INSTALL.md
diff --git a/INSTALL.md b/INSTALL.md
index 74e3e79..53a6e9e 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -9,13 +9,13 @@
[bzip2](http://bzip.org/).
For supporting xz-compressed zip archives, you need
-[liblzma](https://tukaani.org/xz/) which is part of xz.
+[liblzma](https://tukaani.org/xz/) which is part of xz, at least version 5.2.
For AES (encryption) support, you need one of these cryptographic libraries,
listed in order of preference:
- Apple's CommonCrypto (available on macOS and iOS)
-- [GnuTLS](https://www.gnutls.org/)
+- [GnuTLS](https://www.gnutls.org/) and [Nettle](https://www.lysator.liu.se/~nisse/nettle/) (at least nettle 3.0)
- [mbed TLS](https://tls.mbed.org/)
- [OpenSSL](https://www.openssl.org/) >= 1.0.
- Microsoft Windows Cryptography Framework
