diff --git a/lib/blockchain.py b/lib/blockchain.py
index cea971e6..784b56dd 100644
--- a/lib/blockchain.py
+++ b/lib/blockchain.py
@@ -84,7 +84,10 @@ def hash_header(header):
     if header is None:
         return '0' * 64
     if header.get('prev_block_hash') is None:
-        header['prev_block_hash'] = '00'*64 ''' TODO 32? '''
+        header['prev_block_hash'] = '00'*64
+        '''
+        TODO 32?
+        '''
     return hash_encode(Hash(bfh(serialize_header(header))))
 
 
diff --git a/lib/constants.py b/lib/constants.py
index ec35cbe3..6b93e04b 100644
--- a/lib/constants.py
+++ b/lib/constants.py
@@ -37,18 +37,26 @@ def read_json(filename, default):
     return r
 
 
+
+
 class BitcoinMainnet:
 
     TESTNET = False
     WIF_PREFIX = 0x80
-    ADDRTYPE_P2PKH = 0
-    ADDRTYPE_P2SH = 5
-    SEGWIT_HRP = "bc"
-    GENESIS = "000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f"
+    ADDRTYPE_P2PKH = [0x1C, 0xB8] 
+    ADDRTYPE_P2SH = [0x1C, 0xBD]
+    ADDRTYPE_SHIELDED = [0x16, 0x9A]
+    SEGWIT_HRP = "bc" # (No ZCL Segwit)
+    GENESIS = "0007104ccda289427919efc39dc9e4d499804b7bebc22df55f8b834301260602"
     DEFAULT_PORTS = {'t': '50001', 's': '50002'}
     DEFAULT_SERVERS = read_json('servers.json', {})
     CHECKPOINTS = read_json('checkpoints.json', [])
 
+    EQUIHASH_N = 200
+    EQUIHASH_K = 9
+
+    CHUNK_SIZE = 200
+
     XPRV_HEADERS = {
         'standard':    0x0488ade4,  # xprv
         'p2wpkh-p2sh': 0x049d7878,  # yprv
@@ -69,14 +77,20 @@ class BitcoinTestnet:
 
     TESTNET = True
     WIF_PREFIX = 0xef
-    ADDRTYPE_P2PKH = 111
-    ADDRTYPE_P2SH = 196
-    SEGWIT_HRP = "tb"
+    ADDRTYPE_P2PKH = [0x1D, 0x25] 
+    ADDRTYPE_P2SH = [0x1C, 0xBA] 
+    ADDTYPE_SHIELDED = [0x16, 0xB6]
+    SEGWIT_HRP = "tb" # (ZCL has no Segwit)
     GENESIS = "000000000933ea01ad0ee984209779baaec3ced90fa3f408719526f8d77f4943"
     DEFAULT_PORTS = {'t': '51001', 's': '51002'}
     DEFAULT_SERVERS = read_json('servers_testnet.json', {})
     CHECKPOINTS = read_json('checkpoints_testnet.json', [])
 
+    EQUIHASH_N = 200
+    EQUIHASH_K = 9
+
+    CHUNK_SIZE = 200
+
     XPRV_HEADERS = {
         'standard':    0x04358394,  # tprv
         'p2wpkh-p2sh': 0x044a4e28,  # uprv
diff --git a/lib/interface.py b/lib/interface.py
index 6a741bff..81382826 100644
--- a/lib/interface.py
+++ b/lib/interface.py
@@ -31,9 +31,7 @@ import threading
 import time
 import traceback
 
-from .util import print_error, get_cert_path
-
-ca_path = get_cert_path()
+from .util import print_error
 
 from . import util
 from . import x509
diff --git a/lib/servers.json b/lib/servers.json
index c6b5588b..bf03998a 100644
--- a/lib/servers.json
+++ b/lib/servers.json
@@ -1,5 +1,5 @@
 {
-    "electrum.zclassic.org": {"s":"5222"},
-    "zcl-electrum.com": {"s":"50002"}
+    "electrum.zclassic.org": {"s":"5222", "pruning": "-", "version": "1.1"},
+    "zcl-electrum.com": {"s":"50002", "pruning": "-", "version": "1.1"}
 }
 
diff --git a/lib/x509.py b/lib/x509.py
index 46933251..122aa730 100644
--- a/lib/x509.py
+++ b/lib/x509.py
@@ -23,7 +23,7 @@
 # CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 from . import util
-from .util import profiler, bh2u, get_cert_path
+from .util import profiler, bh2u
 import ecdsa
 import hashlib