diff --git a/README.md b/README.md
index 4d4c2c2..1e5efdc 100644
--- a/README.md
+++ b/README.md
@@ -37,7 +37,7 @@ Commands:
   cfstats   Detailed statistics about cells in a column family
   pstats    Partition size statistics for a column family
   purge     Statistics about reclaimable data for a column family
-  sstables  Print out metadata for sstables the belong to a column family
+  sstables  Print out metadata for sstables that belong to a column family
   summary   Summary information about all column families including how much of the data is repaired
 ```
 
diff --git a/pom.xml b/pom.xml
index 3bfc010..ac3657d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -4,7 +4,7 @@
     <modelVersion>4.0.0</modelVersion>
     
     <groupId>com.instaclustr</groupId>
-    <artifactId>ic-sstable-tools-4.0.0</artifactId>
+    <artifactId>ic-sstable-tools-4.1.0</artifactId>
     <version>1.0.0</version>
     
     <name>Instaclustr SSTable Tools</name>
@@ -88,7 +88,7 @@
         <dependency>
             <groupId>org.apache.cassandra</groupId>
             <artifactId>cassandra-all</artifactId>
-            <version>4.0.0</version>
+            <version>4.1.0</version>
             <scope>provided</scope>
         </dependency>
     </dependencies>
diff --git a/src/deb/control/control b/src/deb/control/control
index 60d8901..b5cfd44 100644
--- a/src/deb/control/control
+++ b/src/deb/control/control
@@ -3,5 +3,5 @@ Version: [[version]]
 Section: misc
 Priority: optional
 Architecture: all
-Depends: cassandra (>= 4.0)
+Depends: cassandra (>= 4.1)
 Maintainer: [[maintainer]]
diff --git a/src/main/java/com/instaclustr/sstabletools/Histogram.java b/src/main/java/com/instaclustr/sstabletools/Histogram.java
index 20f5ddb..cc98ecc 100644
--- a/src/main/java/com/instaclustr/sstabletools/Histogram.java
+++ b/src/main/java/com/instaclustr/sstabletools/Histogram.java
@@ -81,7 +81,7 @@ protected int size() {
     }
 
     /**
-     * Snapshot histogram.
+     * @return snapshot histogram.
      */
     public Snapshot snapshot() {
         final int s = size();
diff --git a/src/main/java/com/instaclustr/sstabletools/ProgressBar.java b/src/main/java/com/instaclustr/sstabletools/ProgressBar.java
index 992d243..769b889 100644
--- a/src/main/java/com/instaclustr/sstabletools/ProgressBar.java
+++ b/src/main/java/com/instaclustr/sstabletools/ProgressBar.java
@@ -33,6 +33,7 @@ public final class ProgressBar {
      * Construct progress bar.
      *
      * @param title Progress bar title
+     * @param interactive whether bar is interactive or not
      */
     public ProgressBar(String title, boolean interactive) {
         this.title = title;
diff --git a/src/main/java/com/instaclustr/sstabletools/PurgeStatistics.java b/src/main/java/com/instaclustr/sstabletools/PurgeStatistics.java
index a24ec59..6634870 100644
--- a/src/main/java/com/instaclustr/sstabletools/PurgeStatistics.java
+++ b/src/main/java/com/instaclustr/sstabletools/PurgeStatistics.java
@@ -1,6 +1,7 @@
 package com.instaclustr.sstabletools;
 
 import org.apache.cassandra.db.DecoratedKey;
+import org.apache.cassandra.io.sstable.SSTableId;
 
 import java.util.ArrayList;
 import java.util.Comparator;
@@ -26,7 +27,7 @@ public int compare(PurgeStatistics o1, PurgeStatistics o2) {
     /**
      * List of generations the key belongs to.
      */
-    public List<Integer> generations = new ArrayList<>();
+    public List<SSTableId> ssTableIds = new ArrayList<>();
 
     /**
      * Size in bytes of current partition.
diff --git a/src/main/java/com/instaclustr/sstabletools/PurgeStatisticsCollector.java b/src/main/java/com/instaclustr/sstabletools/PurgeStatisticsCollector.java
index 4396f5b..6f37069 100644
--- a/src/main/java/com/instaclustr/sstabletools/PurgeStatisticsCollector.java
+++ b/src/main/java/com/instaclustr/sstabletools/PurgeStatisticsCollector.java
@@ -94,7 +94,7 @@ public void run() {
                     cfProxy.formatKey(stats.key),
                     Util.humanReadableByteCount(stats.size),
                     Util.humanReadableByteCount(stats.reclaimable),
-                    stats.generations.toString()
+                    stats.ssTableIds.toString()
                 );
             }
             System.out.println(tb);
diff --git a/src/main/java/com/instaclustr/sstabletools/SSTableMetadata.java b/src/main/java/com/instaclustr/sstabletools/SSTableMetadata.java
index c99b35b..0b25444 100644
--- a/src/main/java/com/instaclustr/sstabletools/SSTableMetadata.java
+++ b/src/main/java/com/instaclustr/sstabletools/SSTableMetadata.java
@@ -1,7 +1,11 @@
 package com.instaclustr.sstabletools;
 
+import org.apache.cassandra.io.sstable.SSTableId;
+
 import java.util.Comparator;
 
+import static com.instaclustr.sstabletools.Util.compareIds;
+
 /**
  * Metadata statistics about sstable.
  */
@@ -10,7 +14,7 @@ public class SSTableMetadata {
         @Override
         public int compare(SSTableMetadata o1, SSTableMetadata o2) {
             int cmp = Long.compare(o1.minTimestamp, o2.minTimestamp);
-            return cmp == 0 ? Integer.compare(o1.generation, o2.generation) : cmp;
+            return compareIds(cmp, o1.ssTableId, o2.ssTableId);
         }
     };
 
@@ -18,14 +22,14 @@ public int compare(SSTableMetadata o1, SSTableMetadata o2) {
         @Override
         public int compare(SSTableMetadata o1, SSTableMetadata o2) {
             int cmp = Long.compare(o1.maxTimestamp, o2.maxTimestamp);
-            return cmp == 0 ? Integer.compare(o1.generation, o2.generation) : cmp;
+            return compareIds(cmp, o1.ssTableId, o2.ssTableId);
         }
     };
 
     public final static Comparator<SSTableMetadata> GENERATION_COMPARATOR = new Comparator<SSTableMetadata>() {
         @Override
         public int compare(SSTableMetadata o1, SSTableMetadata o2) {
-            return Integer.compare(o1.generation, o2.generation);
+            return compareIds(0, o1.ssTableId, o2.ssTableId);
         }
     };
 
@@ -33,7 +37,7 @@ public int compare(SSTableMetadata o1, SSTableMetadata o2) {
         @Override
         public int compare(SSTableMetadata o1, SSTableMetadata o2) {
             int cmp = Long.compare(o1.level, o2.level);
-            return cmp == 0 ? Integer.compare(o1.generation, o2.generation) : cmp;
+            return compareIds(cmp, o1.ssTableId, o2.ssTableId);
         }
     };
 
@@ -45,7 +49,7 @@ public int compare(SSTableMetadata o1, SSTableMetadata o2) {
     /**
      * SSTable generation.
      */
-    public int generation;
+    public SSTableId ssTableId;
 
     public long minTimestamp;
 
diff --git a/src/main/java/com/instaclustr/sstabletools/SSTableStatistics.java b/src/main/java/com/instaclustr/sstabletools/SSTableStatistics.java
index a3dcbb0..a3df759 100644
--- a/src/main/java/com/instaclustr/sstabletools/SSTableStatistics.java
+++ b/src/main/java/com/instaclustr/sstabletools/SSTableStatistics.java
@@ -1,16 +1,21 @@
 package com.instaclustr.sstabletools;
 
+import org.apache.cassandra.io.sstable.SSTableId;
+import org.apache.cassandra.io.sstable.SequenceBasedSSTableId;
+import org.apache.cassandra.io.sstable.UUIDBasedSSTableId;
+
 import java.util.Comparator;
 
 /**
  * SSTable statistics.
  */
 public class SSTableStatistics {
+
     public final static Comparator<SSTableStatistics> LIVENESS_COMPARATOR = new Comparator<SSTableStatistics>() {
         @Override
         public int compare(SSTableStatistics o1, SSTableStatistics o2) {
             int cmp = Long.compare(o1.getLiveness(), o2.getLiveness());
-            return cmp == 0 ? Integer.compare(o1.generation, o2.generation) : cmp;
+            return Util.compareIds(cmp, o1.ssTableId, o2.ssTableId);
         }
     };
 
@@ -18,7 +23,7 @@ public int compare(SSTableStatistics o1, SSTableStatistics o2) {
         @Override
         public int compare(SSTableStatistics o1, SSTableStatistics o2) {
             int cmp = Long.compare(o1.minTimestamp, o2.minTimestamp);
-            return cmp == 0 ? Integer.compare(o1.generation, o2.generation) : cmp;
+            return Util.compareIds(cmp, o1.ssTableId, o2.ssTableId);
         }
     };
 
@@ -26,14 +31,14 @@ public int compare(SSTableStatistics o1, SSTableStatistics o2) {
         @Override
         public int compare(SSTableStatistics o1, SSTableStatistics o2) {
             int cmp = Long.compare(o1.maxTimestamp, o2.maxTimestamp);
-            return cmp == 0 ? Integer.compare(o1.generation, o2.generation) : cmp;
+            return Util.compareIds(cmp, o1.ssTableId, o2.ssTableId);
         }
     };
 
     /**
-     * SSTable generation.
+     * SSTable id.
      */
-    public int generation;
+    public SSTableId ssTableId;
 
     /**
      * File name of SSTable Data.db.
@@ -123,15 +128,15 @@ public int compare(SSTableStatistics o1, SSTableStatistics o2) {
     /**
      * Construct statistics record for SSTable.
      *
-     * @param generation         SSTable Generation
+     * @param ssTableId         SSTable id
      * @param filename           Filename of Data.db
      * @param uncompressedLength Uncompressed length of SSTable Data.db in bytes
      * @param minTimestamp       Minimum timestamp of SSTable
      * @param maxTimestamp       Maximum timestamp of SSTable
      * @param level              SSTable LTCS level
      */
-    public SSTableStatistics(int generation, String filename, long uncompressedLength, long minTimestamp, long maxTimestamp, int level) {
-        this.generation = generation;
+    public SSTableStatistics(SSTableId ssTableId, String filename, long uncompressedLength, long minTimestamp, long maxTimestamp, int level) {
+        this.ssTableId = ssTableId;
         this.filename = filename;
         this.size = uncompressedLength;
         this.minTimestamp = minTimestamp;
diff --git a/src/main/java/com/instaclustr/sstabletools/Util.java b/src/main/java/com/instaclustr/sstabletools/Util.java
index e7fff36..2ce763f 100644
--- a/src/main/java/com/instaclustr/sstabletools/Util.java
+++ b/src/main/java/com/instaclustr/sstabletools/Util.java
@@ -1,5 +1,9 @@
 package com.instaclustr.sstabletools;
 
+import org.apache.cassandra.io.sstable.SSTableId;
+import org.apache.cassandra.io.sstable.SequenceBasedSSTableId;
+import org.apache.cassandra.io.sstable.UUIDBasedSSTableId;
+
 import java.text.SimpleDateFormat;
 import java.util.Random;
 import java.util.TimeZone;
@@ -25,6 +29,16 @@ public final class Util {
         rand = new Random();
     }
 
+    public static int compareIds(int cmp, SSTableId o1, SSTableId o2) {
+        if (o1 instanceof UUIDBasedSSTableId) {
+            return cmp == 0 ? ((UUIDBasedSSTableId) o1).compareTo((UUIDBasedSSTableId) o2) : cmp;
+        } else if (o1 instanceof SequenceBasedSSTableId) {
+            return cmp == 0 ? ((SequenceBasedSSTableId) o1).compareTo((SequenceBasedSSTableId) o2) : cmp;
+        } else {
+            throw new IllegalStateException("Unable to process SSTableId of type " + o1.getClass());
+        }
+    }
+
     public static String humanReadableByteCount(long bytes) {
         return humanReadableByteCount(bytes, true);
     }
diff --git a/src/main/java/com/instaclustr/sstabletools/cassandra/CassandraBackend.java b/src/main/java/com/instaclustr/sstabletools/cassandra/CassandraBackend.java
index 9f81c3a..a3da7e1 100644
--- a/src/main/java/com/instaclustr/sstabletools/cassandra/CassandraBackend.java
+++ b/src/main/java/com/instaclustr/sstabletools/cassandra/CassandraBackend.java
@@ -21,9 +21,10 @@
 import java.io.IOException;
 import java.nio.file.Files;
 import java.util.*;
+import java.util.stream.Collectors;
 
 /**
- * Proxy to Cassandra 3.0 backend.
+ * Proxy to Cassandra 4.1 backend.
  */
 public class CassandraBackend implements CassandraProxy {
     private static final CassandraBackend singleton = new CassandraBackend();
@@ -34,19 +35,22 @@ public static CassandraProxy getInstance() {
 
     static {
         Util.initDatabaseDescriptor();
-        Schema.instance.loadFromDisk(false);
+        Schema.instance.loadFromDisk();
     }
 
     private CassandraBackend() {}
 
     public List<String> getKeyspaces() {
-        List<String> names = new ArrayList<>(Schema.instance.getNonSystemKeyspaces());
-        Collections.sort(names);
-        return names;
+        return Schema.instance.getNonLocalStrategyKeyspaces()
+                     .stream()
+                     .map(ksmd -> ksmd.name).sorted().collect(Collectors.toList());
     }
 
     public List<String> getColumnFamilies(String ksName) {
         KeyspaceMetadata ksMetaData = Schema.instance.getKeyspaceMetadata(ksName);
+        if (ksMetaData == null) {
+            throw new IllegalStateException("Unknown keyspace " + ksMetaData.name);
+        }
         List<String> names = new ArrayList<>(ksMetaData.tables.size() + ksMetaData.views.size());
         for (TableMetadata cfMetaData : ksMetaData.tablesAndViews()) {
             names.add(cfMetaData.name);
@@ -58,7 +62,7 @@ public List<String> getColumnFamilies(String ksName) {
     private ColumnFamilyStore getStore(String ksName, String cfName) {
         // Start by validating keyspace name
         if (Schema.instance.getKeyspaceMetadata(ksName) == null) {
-            System.err.println(String.format("Reference to nonexistent keyspace: %s!", ksName));
+            System.err.printf("Reference to nonexistent keyspace: %s!%n", ksName);
             System.exit(1);
         }
         Keyspace keyspace = Keyspace.open(ksName);
@@ -74,9 +78,9 @@ private ColumnFamilyStore getStore(String ksName, String cfName) {
         try {
             return keyspace.getColumnFamilyStore(baseName);
         } catch (Throwable t) {
-            System.err.println(String.format(
-                    "The provided column family is not part of this cassandra keyspace: keyspace = %s, column family = %s",
-                    ksName, cfName));
+            System.err.printf(
+                    "The provided column family is not part of this cassandra keyspace: keyspace = %s, column family = %s%n",
+                    ksName, cfName);
             System.exit(1);
         }
         return null;
@@ -90,7 +94,7 @@ public List<SSTableMetadata> getSSTableMetadata(String ksName, String cfName) {
             SSTableMetadata tableMetadata = new SSTableMetadata();
             File dataFile = new File(table.descriptor.filenameFor(Component.DATA));
             tableMetadata.filename = dataFile.getName();
-            tableMetadata.generation = table.descriptor.generation;
+            tableMetadata.ssTableId = table.descriptor.id;
             try {
                 tableMetadata.fileTimestamp = Files.getLastModifiedTime(dataFile.toPath()).toMillis();
             } catch (IOException e) {
@@ -131,7 +135,7 @@ public ColumnFamilyProxy getColumnFamily(String ksName, String cfName, String sn
                     snapshotName,
                     filter);
         } catch (Throwable t) {
-            System.err.println(String.format("Error retrieving snapshot for %s.%s", ksName, cfName));
+            System.err.printf("Error retrieving snapshot for %s.%s%n", ksName, cfName);
             System.exit(1);
         }
 
@@ -144,7 +148,7 @@ public Class getCompactionClass(String ksName, String cfName) {
             TableMetadata metaData = Schema.instance.getTableMetadata(ksName, cfName);
             return metaData.params.compaction.klass();
         } catch (Throwable t) {
-            System.err.println(String.format("Error retrieving snapshot for %s.%s", ksName, cfName));
+            System.err.printf("Error retrieving snapshot for %s.%s%n", ksName, cfName);
             System.exit(1);
         }
 
diff --git a/src/main/java/com/instaclustr/sstabletools/cassandra/ColumnFamilyBackend.java b/src/main/java/com/instaclustr/sstabletools/cassandra/ColumnFamilyBackend.java
index cc30d84..5c0729a 100644
--- a/src/main/java/com/instaclustr/sstabletools/cassandra/ColumnFamilyBackend.java
+++ b/src/main/java/com/instaclustr/sstabletools/cassandra/ColumnFamilyBackend.java
@@ -1,6 +1,5 @@
 package com.instaclustr.sstabletools.cassandra;
 
-import com.google.common.util.concurrent.RateLimiter;
 import com.instaclustr.sstabletools.*;
 import org.apache.cassandra.db.ColumnFamilyStore;
 import org.apache.cassandra.db.DecoratedKey;
@@ -9,6 +8,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
@@ -66,7 +66,7 @@ public ColumnFamilyBackend(AbstractType<?> keyValidator,
             this.clearSnapshot = false;
         } else {
             snapshotName = Util.generateSnapshotName();
-            cfStore.snapshotWithoutFlush(snapshotName, null, true, null);
+            cfStore.snapshotWithoutMemtable(snapshotName, null, true, null, null, Instant.now());
             this.clearSnapshot = true;
         }
         this.snapshotName = snapshotName;
@@ -91,7 +91,7 @@ public Collection<SSTableReader> getIndexReaders() {
                 File dataFile = new File(sstable.descriptor.filenameFor(Component.DATA));
                 readers.add(new IndexReader(
                         new SSTableStatistics(
-                                sstable.descriptor.generation,
+                                sstable.descriptor.id,
                                 dataFile.getName(),
                                 sstable.uncompressedLength(),
                                 sstable.getMinTimestamp(),
@@ -101,7 +101,9 @@ public Collection<SSTableReader> getIndexReaders() {
                         sstable.descriptor.version,
                         sstable.getPartitioner()
                 ));
-            } catch (Throwable t) {}
+            } catch (Throwable t) {
+
+            }
         }
         return readers;
     }
@@ -114,7 +116,7 @@ public Collection<SSTableReader> getDataReaders() {
                 File dataFile = new File(sstable.descriptor.filenameFor(Component.DATA));
                 readers.add(new DataReader(
                         new SSTableStatistics(
-                                sstable.descriptor.generation,
+                                sstable.descriptor.id,
                                 dataFile.getName(),
                                 sstable.uncompressedLength(),
                                 sstable.getMinTimestamp(),
diff --git a/src/main/java/com/instaclustr/sstabletools/cassandra/DataReader.java b/src/main/java/com/instaclustr/sstabletools/cassandra/DataReader.java
index ae3af58..0775953 100644
--- a/src/main/java/com/instaclustr/sstabletools/cassandra/DataReader.java
+++ b/src/main/java/com/instaclustr/sstabletools/cassandra/DataReader.java
@@ -29,9 +29,11 @@ public class DataReader extends AbstractSSTableReader {
     private long position;
 
     /**
-     * Construct a reader for Index.db sstable file.
+     * Construct a reader for Data.db sstable file.
      *
      * @param tableStats  SSTable statistics.
+     * @param scanner scanner of sstables
+     * @param gcGrace gc_grace of table
      */
     public DataReader(SSTableStatistics tableStats, ISSTableScanner scanner, int gcGrace) {
         this.tableStats = tableStats;
diff --git a/src/main/java/com/instaclustr/sstabletools/cassandra/IndexReader.java b/src/main/java/com/instaclustr/sstabletools/cassandra/IndexReader.java
index 446be14..b88c502 100644
--- a/src/main/java/com/instaclustr/sstabletools/cassandra/IndexReader.java
+++ b/src/main/java/com/instaclustr/sstabletools/cassandra/IndexReader.java
@@ -50,6 +50,7 @@ public class IndexReader extends AbstractSSTableReader {
      *
      * @param tableStats  SSTable statistics.
      * @param reader      Reader to Index.db file.
+     * @param version     Version of SSTable
      * @param partitioner The sstable partitioner.
      */
     public IndexReader(SSTableStatistics tableStats, RandomAccessReader reader, Version version, IPartitioner partitioner) {
diff --git a/src/main/java/com/instaclustr/sstabletools/cassandra/PurgeStatisticBackend.java b/src/main/java/com/instaclustr/sstabletools/cassandra/PurgeStatisticBackend.java
index 0322493..56b3956 100644
--- a/src/main/java/com/instaclustr/sstabletools/cassandra/PurgeStatisticBackend.java
+++ b/src/main/java/com/instaclustr/sstabletools/cassandra/PurgeStatisticBackend.java
@@ -1,19 +1,14 @@
 package com.instaclustr.sstabletools.cassandra;
 
-import com.google.common.util.concurrent.RateLimiter;
 import com.instaclustr.sstabletools.PurgeStatistics;
 import com.instaclustr.sstabletools.PurgeStatisticsReader;
 import com.instaclustr.sstabletools.Util;
-import org.apache.cassandra.db.rows.UnfilteredRowIterators.MergeListener;
-import org.apache.cassandra.io.sstable.format.big.BigTableReader;
-import org.apache.cassandra.io.sstable.format.big.BigTableScanner;
-import org.apache.cassandra.schema.TableMetadata;
 import org.apache.cassandra.db.*;
 import org.apache.cassandra.db.filter.ColumnFilter;
-import org.apache.cassandra.db.partitions.PurgeFunction;
 import org.apache.cassandra.db.rows.*;
 import org.apache.cassandra.db.transform.Transformation;
 import org.apache.cassandra.io.sstable.ISSTableScanner;
+import org.apache.cassandra.io.sstable.SSTableId;
 import org.apache.cassandra.net.MessagingService;
 import org.apache.cassandra.utils.ByteBufferUtil;
 
@@ -54,7 +49,7 @@ public PurgeStatisticBackend(ColumnFamilyStore cfs, Collection<org.apache.cassan
         readerQueue = new PriorityQueue<>(sstables.size());
         for (org.apache.cassandra.io.sstable.format.SSTableReader sstable : sstables) {
             length += sstable.uncompressedLength();
-            ScannerWrapper scanner = new ScannerWrapper(sstable.descriptor.generation, sstable.getScanner());
+            ScannerWrapper scanner = new ScannerWrapper(sstable.descriptor.id, sstable.getScanner());
             if (scanner.next()) {
                 readerQueue.add(scanner);
             }
@@ -127,7 +122,7 @@ private void onUnfiltered(Unfiltered unfiltered) {
                 }
             });
             rows.add(row);
-            stats.generations.add(scannerWrapper.generation);
+            stats.ssTableIds.add(scannerWrapper.ssTableId);
         }
 
         // Merge rows together and grab column statistics.
@@ -285,7 +280,7 @@ private class ScannerWrapper implements Comparable<ScannerWrapper> {
         /**
          * Generation of sstable being scanned.
          */
-        public int generation;
+        public SSTableId ssTableId;
 
         /**
          * SSTable scanner.
@@ -302,8 +297,8 @@ private class ScannerWrapper implements Comparable<ScannerWrapper> {
          */
         private long position;
 
-        public ScannerWrapper(int generation, ISSTableScanner scanner) {
-            this.generation = generation;
+        public ScannerWrapper(SSTableId ssTableId, ISSTableScanner scanner) {
+            this.ssTableId = ssTableId;
             this.scanner = scanner;
             this.position = 0;
         }
diff --git a/src/main/java/com/instaclustr/sstabletools/cli/SSTableMetadataCollector.java b/src/main/java/com/instaclustr/sstabletools/cli/SSTableMetadataCollector.java
index 63f3dfd..4b900f0 100644
--- a/src/main/java/com/instaclustr/sstabletools/cli/SSTableMetadataCollector.java
+++ b/src/main/java/com/instaclustr/sstabletools/cli/SSTableMetadataCollector.java
@@ -23,7 +23,7 @@
     versionProvider = CLI.class,
     name = "sstables",
     usageHelpWidth = 128,
-    description = "Print out metadata for sstables the belong to a column family",
+    description = "Print out metadata for sstables that belong to a column family",
     mixinStandardHelpOptions = true
 )
 public class SSTableMetadataCollector implements Runnable {