diff --git a/src/OpaqueVal.cc b/src/OpaqueVal.cc
index 5f141fe92a..459d2deb4e 100644
--- a/src/OpaqueVal.cc
+++ b/src/OpaqueVal.cc
@@ -706,7 +706,7 @@ BloomFilterVal::BloomFilterVal()
 	bloom_filter = nullptr;
 	}
 
-BloomFilterVal::BloomFilterVal(probabilistic::BloomFilter* bf)
+BloomFilterVal::BloomFilterVal(zeek::probabilistic::BloomFilter* bf)
 	: OpaqueVal(bloomfilter_type)
 	{
 	hash = nullptr;
@@ -784,7 +784,7 @@ BloomFilterValPtr BloomFilterVal::Merge(const BloomFilterVal* x,
 		return nullptr;
 		}
 
-	probabilistic::BloomFilter* copy = x->bloom_filter->Clone();
+	zeek::probabilistic::BloomFilter* copy = x->bloom_filter->Clone();
 
 	if ( ! copy->Merge(y->bloom_filter) )
 		{
@@ -851,7 +851,7 @@ bool BloomFilterVal::DoUnserialize(const broker::data& data)
 			return false;
 		}
 
-	auto bf = probabilistic::BloomFilter::Unserialize((*v)[1]);
+	auto bf = zeek::probabilistic::BloomFilter::Unserialize((*v)[1]);
 	if ( ! bf )
 		return false;
 
@@ -865,7 +865,7 @@ CardinalityVal::CardinalityVal() : OpaqueVal(cardinality_type)
 	hash = nullptr;
 	}
 
-CardinalityVal::CardinalityVal(probabilistic::CardinalityCounter* arg_c)
+CardinalityVal::CardinalityVal(zeek::probabilistic::detail::CardinalityCounter* arg_c)
 	: OpaqueVal(cardinality_type)
 	{
 	c = arg_c;
@@ -881,7 +881,7 @@ CardinalityVal::~CardinalityVal()
 ValPtr CardinalityVal::DoClone(CloneState* state)
 	{
 	return state->NewClone(this,
-			       zeek::make_intrusive<CardinalityVal>(new probabilistic::CardinalityCounter(*c)));
+			       zeek::make_intrusive<CardinalityVal>(new zeek::probabilistic::detail::CardinalityCounter(*c)));
 	}
 
 bool CardinalityVal::Typify(zeek::TypePtr arg_type)
@@ -945,7 +945,7 @@ bool CardinalityVal::DoUnserialize(const broker::data& data)
 			return false;
 		}
 
-	auto cu = probabilistic::CardinalityCounter::Unserialize((*v)[1]);
+	auto cu = zeek::probabilistic::detail::CardinalityCounter::Unserialize((*v)[1]);
 	if ( ! cu )
 		return false;
 
diff --git a/src/OpaqueVal.h b/src/OpaqueVal.h
index ce223b277e..8b8dcf1cac 100644
--- a/src/OpaqueVal.h
+++ b/src/OpaqueVal.h
@@ -14,10 +14,8 @@
 
 namespace broker { class data; }
 
-namespace probabilistic {
-	class BloomFilter;
-	class CardinalityCounter;
-}
+ZEEK_FORWARD_DECLARE_NAMESPACED(BloomFilter, zeek, probabilistic);
+ZEEK_FORWARD_DECLARE_NAMESPACED(CardinalityCounter, zeek, probabilistic, detail);
 
 namespace zeek {
 
@@ -306,7 +304,7 @@ private:
 
 class BloomFilterVal : public OpaqueVal {
 public:
-	explicit BloomFilterVal(probabilistic::BloomFilter* bf);
+	explicit BloomFilterVal(zeek::probabilistic::BloomFilter* bf);
 	~BloomFilterVal() override;
 
 	ValPtr DoClone(CloneState* state) override;
@@ -337,13 +335,13 @@ private:
 
 	zeek::TypePtr type;
 	zeek::detail::CompositeHash* hash;
-	probabilistic::BloomFilter* bloom_filter;
+	zeek::probabilistic::BloomFilter* bloom_filter;
 };
 
 
 class CardinalityVal : public OpaqueVal {
 public:
-	explicit CardinalityVal(probabilistic::CardinalityCounter*);
+	explicit CardinalityVal(zeek::probabilistic::detail::CardinalityCounter*);
 	~CardinalityVal() override;
 
 	ValPtr DoClone(CloneState* state) override;
@@ -355,7 +353,7 @@ public:
 
 	bool Typify(zeek::TypePtr type);
 
-	probabilistic::CardinalityCounter* Get()	{ return c; };
+	zeek::probabilistic::detail::CardinalityCounter* Get()	{ return c; };
 
 protected:
 	CardinalityVal();
@@ -364,7 +362,7 @@ protected:
 private:
 	zeek::TypePtr type;
 	zeek::detail::CompositeHash* hash;
-	probabilistic::CardinalityCounter* c;
+	zeek::probabilistic::detail::CardinalityCounter* c;
 };
 
 class ParaglobVal : public OpaqueVal {
diff --git a/src/probabilistic/BitVector.cc b/src/probabilistic/BitVector.cc
index c37a57b69a..92014df714 100644
--- a/src/probabilistic/BitVector.cc
+++ b/src/probabilistic/BitVector.cc
@@ -10,7 +10,7 @@
 
 #include "digest.h"
 
-using namespace probabilistic;
+namespace zeek::probabilistic::detail {
 
 BitVector::size_type BitVector::npos = static_cast<BitVector::size_type>(-1);
 BitVector::block_type BitVector::bits_per_block =
@@ -263,8 +263,6 @@ BitVector& BitVector::operator-=(BitVector const& other)
 	return *this;
 	}
 
-namespace probabilistic {
-
 BitVector operator&(BitVector const& x, BitVector const& y)
 	{
 	BitVector b(x);
@@ -318,8 +316,6 @@ bool operator<(BitVector const& x, BitVector const& y)
 	return false;
 	}
 
-}
-
 void BitVector::Resize(size_type n, bool value)
 	{
 	size_type old = Blocks();
@@ -581,3 +577,5 @@ BitVector::size_type BitVector::find_from(size_type i) const
 
 	return i * bits_per_block + lowest_bit(bits[i]);
 	}
+
+} // namespace zeek::probabilistic::detail
diff --git a/src/probabilistic/BitVector.h b/src/probabilistic/BitVector.h
index cbbcedd80b..84e745bffb 100644
--- a/src/probabilistic/BitVector.h
+++ b/src/probabilistic/BitVector.h
@@ -10,7 +10,7 @@
 
 namespace broker { class data; }
 
-namespace probabilistic {
+namespace zeek::probabilistic::detail {
 
 /**
  * A vector of bits.
@@ -356,4 +356,8 @@ private:
 	size_type num_bits;
 };
 
+} // namespace zeek::probabilistic::detail
+
+namespace probabilistic {
+	using BitVector [[deprecated("Remove in v4.1. Use zeek::probabilistic::detail::BitVector.")]] = zeek::probabilistic::detail::BitVector;
 }
diff --git a/src/probabilistic/BloomFilter.cc b/src/probabilistic/BloomFilter.cc
index ce175c5283..0d6fdb4cd7 100644
--- a/src/probabilistic/BloomFilter.cc
+++ b/src/probabilistic/BloomFilter.cc
@@ -13,14 +13,14 @@
 #include "../util.h"
 #include "../Reporter.h"
 
-using namespace probabilistic;
+namespace zeek::probabilistic {
 
 BloomFilter::BloomFilter()
 	{
 	hasher = nullptr;
 	}
 
-BloomFilter::BloomFilter(const Hasher* arg_hasher)
+BloomFilter::BloomFilter(const detail::Hasher* arg_hasher)
 	{
 	hasher = arg_hasher;
 	}
@@ -56,7 +56,7 @@ std::unique_ptr<BloomFilter> BloomFilter::Unserialize(const broker::data& data)
 	if ( ! type )
 		return nullptr;
 
-	auto hasher_ = Hasher::Unserialize((*v)[1]);
+	auto hasher_ = detail::Hasher::Unserialize((*v)[1]);
 	if ( ! hasher_ )
 		return nullptr;
 
@@ -130,7 +130,7 @@ BasicBloomFilter* BasicBloomFilter::Clone() const
 	BasicBloomFilter* copy = new BasicBloomFilter();
 
 	copy->hasher = hasher->Clone();
-	copy->bits = new BitVector(*bits);
+	copy->bits = new detail::BitVector(*bits);
 
 	return copy;
 	}
@@ -145,10 +145,10 @@ BasicBloomFilter::BasicBloomFilter()
 	bits = nullptr;
 	}
 
-BasicBloomFilter::BasicBloomFilter(const Hasher* hasher, size_t cells)
+BasicBloomFilter::BasicBloomFilter(const detail::Hasher* hasher, size_t cells)
 	: BloomFilter(hasher)
 	{
-	bits = new BitVector(cells);
+	bits = new detail::BitVector(cells);
 	}
 
 BasicBloomFilter::~BasicBloomFilter()
@@ -158,7 +158,7 @@ BasicBloomFilter::~BasicBloomFilter()
 
 void BasicBloomFilter::Add(const zeek::detail::HashKey* key)
 	{
-	Hasher::digest_vector h = hasher->Hash(key);
+	detail::Hasher::digest_vector h = hasher->Hash(key);
 
 	for ( size_t i = 0; i < h.size(); ++i )
 		bits->Set(h[i] % bits->Size());
@@ -166,7 +166,7 @@ void BasicBloomFilter::Add(const zeek::detail::HashKey* key)
 
 size_t BasicBloomFilter::Count(const zeek::detail::HashKey* key) const
 	{
-	Hasher::digest_vector h = hasher->Hash(key);
+	detail::Hasher::digest_vector h = hasher->Hash(key);
 
 	for ( size_t i = 0; i < h.size(); ++i )
 		{
@@ -185,7 +185,7 @@ broker::expected<broker::data> BasicBloomFilter::DoSerialize() const
 
 bool BasicBloomFilter::DoUnserialize(const broker::data& data)
 	{
-	auto b = BitVector::Unserialize(data);
+	auto b = detail::BitVector::Unserialize(data);
 	if ( ! b )
 		return false;
 
@@ -198,11 +198,11 @@ CountingBloomFilter::CountingBloomFilter()
 	cells = nullptr;
 	}
 
-CountingBloomFilter::CountingBloomFilter(const Hasher* hasher,
-					 size_t arg_cells, size_t width)
+CountingBloomFilter::CountingBloomFilter(const detail::Hasher* hasher,
+                                         size_t arg_cells, size_t width)
 	: BloomFilter(hasher)
 	{
-	cells = new CounterVector(width, arg_cells);
+	cells = new detail::CounterVector(width, arg_cells);
 	}
 
 CountingBloomFilter::~CountingBloomFilter()
@@ -249,7 +249,7 @@ CountingBloomFilter* CountingBloomFilter::Clone() const
 	CountingBloomFilter* copy = new CountingBloomFilter();
 
 	copy->hasher = hasher->Clone();
-	copy->cells = new CounterVector(*cells);
+	copy->cells = new detail::CounterVector(*cells);
 
 	return copy;
 	}
@@ -262,7 +262,7 @@ std::string CountingBloomFilter::InternalState() const
 // TODO: Use partitioning in add/count to allow for reusing CMS bounds.
 void CountingBloomFilter::Add(const zeek::detail::HashKey* key)
 	{
-	Hasher::digest_vector h = hasher->Hash(key);
+	detail::Hasher::digest_vector h = hasher->Hash(key);
 
 	for ( size_t i = 0; i < h.size(); ++i )
 		cells->Increment(h[i] % cells->Size());
@@ -270,14 +270,14 @@ void CountingBloomFilter::Add(const zeek::detail::HashKey* key)
 
 size_t CountingBloomFilter::Count(const zeek::detail::HashKey* key) const
 	{
-	Hasher::digest_vector h = hasher->Hash(key);
+	detail::Hasher::digest_vector h = hasher->Hash(key);
 
-	CounterVector::size_type min =
-		std::numeric_limits<CounterVector::size_type>::max();
+	detail::CounterVector::size_type min =
+		std::numeric_limits<detail::CounterVector::size_type>::max();
 
 	for ( size_t i = 0; i < h.size(); ++i )
 		{
-		CounterVector::size_type cnt = cells->Count(h[i] % cells->Size());
+		detail::CounterVector::size_type cnt = cells->Count(h[i] % cells->Size());
 		if ( cnt  < min )
 			min = cnt;
 		}
@@ -293,10 +293,12 @@ broker::expected<broker::data> CountingBloomFilter::DoSerialize() const
 
 bool CountingBloomFilter::DoUnserialize(const broker::data& data)
 	{
-	auto c = CounterVector::Unserialize(data);
+	auto c = detail::CounterVector::Unserialize(data);
 	if ( ! c )
 		return false;
 
 	cells = c.release();
 	return true;
 	}
+
+} // namespace zeek::probabilistic
diff --git a/src/probabilistic/BloomFilter.h b/src/probabilistic/BloomFilter.h
index 409d369569..4cf16b0f51 100644
--- a/src/probabilistic/BloomFilter.h
+++ b/src/probabilistic/BloomFilter.h
@@ -2,6 +2,8 @@
 
 #pragma once
 
+#include "zeek-config.h"
+
 #include <memory>
 #include <vector>
 #include <string>
@@ -13,9 +15,9 @@
 
 namespace broker { class data; }
 
-namespace probabilistic {
+ZEEK_FORWARD_DECLARE_NAMESPACED(CounterVector, zeek, probabilistic, detail);
 
-class CounterVector;
+namespace zeek::probabilistic {
 
 /** Types of derived BloomFilter classes. */
 enum BloomFilterType { Basic, Counting };
@@ -94,13 +96,13 @@ protected:
 	 *
 	 * @param hasher The hasher to use for this Bloom filter.
 	 */
-	explicit BloomFilter(const Hasher* hasher);
+	explicit BloomFilter(const detail::Hasher* hasher);
 
 	virtual broker::expected<broker::data> DoSerialize() const = 0;
 	virtual bool DoUnserialize(const broker::data& data) = 0;
 	virtual BloomFilterType Type() const = 0;
 
-	const Hasher* hasher;
+	const detail::Hasher* hasher;
 };
 
 /**
@@ -117,7 +119,7 @@ public:
 	 *
 	 * @param cells The number of cells.
 	 */
-	BasicBloomFilter(const Hasher* hasher, size_t cells);
+	BasicBloomFilter(const detail::Hasher* hasher, size_t cells);
 
 	/**
 	 * Destructor.
@@ -176,7 +178,7 @@ protected:
 		{ return BloomFilterType::Basic; }
 
 private:
-	BitVector* bits;
+	detail::BitVector* bits;
 };
 
 /**
@@ -194,7 +196,7 @@ public:
 	 *
 	 * @param width The maximal bit-width of counter values.
 	 */
-	CountingBloomFilter(const Hasher* hasher, size_t cells, size_t width);
+	CountingBloomFilter(const detail::Hasher* hasher, size_t cells, size_t width);
 
 	/**
 	 * Destructor.
@@ -225,7 +227,19 @@ protected:
 		{ return BloomFilterType::Counting; }
 
 private:
-	CounterVector* cells;
+	detail::CounterVector* cells;
 };
 
-}
+} // namespace zeek::probabilistic
+
+namespace probabilistic {
+
+	using BloomFilterType [[deprecated("Remove in v4.1. Use zeek::probabilistic::BloomFilterType.")]] = zeek::probabilistic::BloomFilterType;
+	constexpr auto Basic [[deprecated("Remove in v4.1. Use zeek::probabilistic::Basic.")]] = zeek::probabilistic::Basic;
+	constexpr auto Counting [[deprecated("Remove in v4.1. Use zeek::probabilistic::Counting.")]] = zeek::probabilistic::Counting;
+
+	using BloomFilter [[deprecated("Remove in v4.1. Use zeek::probabilistic::BloomFilter.")]] = zeek::probabilistic::BloomFilter;
+	using BasicBloomFilter [[deprecated("Remove in v4.1. Use zeek::probabilistic::BasicBloomFilter.")]] = zeek::probabilistic::BasicBloomFilter;
+	using CountingBloomFilter [[deprecated("Remove in v4.1. Use zeek::probabilistic::CountingBloomFilter.")]] = zeek::probabilistic::CountingBloomFilter;
+
+} // namespace probabilistic
diff --git a/src/probabilistic/CardinalityCounter.cc b/src/probabilistic/CardinalityCounter.cc
index 13bdc02e15..db2fa85936 100644
--- a/src/probabilistic/CardinalityCounter.cc
+++ b/src/probabilistic/CardinalityCounter.cc
@@ -10,7 +10,7 @@
 
 #include "Reporter.h"
 
-using namespace probabilistic;
+namespace zeek::probabilistic::detail {
 
 int CardinalityCounter::OptimalB(double error, double confidence) const
 	{
@@ -279,14 +279,15 @@ std::unique_ptr<CardinalityCounter> CardinalityCounter::Unserialize(const broker
 /*
  * Find Last Set bit
  */
-int
-CardinalityCounter::flsll(uint64_t mask)
-{
-        int bit;
+int CardinalityCounter::flsll(uint64_t mask)
+	{
+	int bit;
 
-        if (mask == 0)
-                return (0);
-        for (bit = 1; mask != 1; bit++)
-                mask = (uint64_t)mask >> 1;
-        return (bit);
-}
+	if (mask == 0)
+		return (0);
+	for (bit = 1; mask != 1; bit++)
+		mask = (uint64_t)mask >> 1;
+	return (bit);
+	}
+
+} // namespace zeek::probabilistic::detail
diff --git a/src/probabilistic/CardinalityCounter.h b/src/probabilistic/CardinalityCounter.h
index a36f7aa610..630c65982f 100644
--- a/src/probabilistic/CardinalityCounter.h
+++ b/src/probabilistic/CardinalityCounter.h
@@ -11,7 +11,7 @@
 
 namespace broker { class data; }
 
-namespace probabilistic {
+namespace zeek::probabilistic::detail {
 
 /**
  * A probabilistic cardinality counter using the HyperLogLog algorithm.
@@ -186,4 +186,8 @@ private:
 	int p; // the log2 of m
 };
 
+} // namespace zeek::probabilistic::detail
+
+namespace probabilistic {
+	using CardinalityCounter [[deprecated("Remove in v4.1. Use zeek::probabilistic::detail::CardinalityCounter.")]] = zeek::probabilistic::detail::CardinalityCounter;
 }
diff --git a/src/probabilistic/CounterVector.cc b/src/probabilistic/CounterVector.cc
index d4b073bca1..e308ed0178 100644
--- a/src/probabilistic/CounterVector.cc
+++ b/src/probabilistic/CounterVector.cc
@@ -11,7 +11,7 @@
 #include "BitVector.h"
 #include "util.h"
 
-using namespace probabilistic;
+namespace zeek::probabilistic::detail {
 
 CounterVector::CounterVector(size_t arg_width, size_t cells)
 	{
@@ -143,8 +143,6 @@ CounterVector& CounterVector::Merge(const CounterVector& other)
 	return *this;
 	}
 
-namespace probabilistic {
-
 CounterVector& CounterVector::operator|=(const CounterVector& other)
 	{
 	return Merge(other);
@@ -156,8 +154,6 @@ CounterVector operator|(const CounterVector& x, const CounterVector& y)
 	return cv |= y;
 	}
 
-}
-
 uint64_t CounterVector::Hash() const
 	{
 	return bits->Hash();
@@ -190,5 +186,4 @@ std::unique_ptr<CounterVector> CounterVector::Unserialize(const broker::data& da
 	return cv;
 	}
 
-
-
+} // namespace zeek::probabilistic::detail
diff --git a/src/probabilistic/CounterVector.h b/src/probabilistic/CounterVector.h
index 0cdd05be95..9c3709cb23 100644
--- a/src/probabilistic/CounterVector.h
+++ b/src/probabilistic/CounterVector.h
@@ -2,6 +2,8 @@
 
 #pragma once
 
+#include "zeek-config.h"
+
 #include <cstddef>
 #include <cstdint>
 #include <memory>
@@ -10,9 +12,9 @@
 
 namespace broker { class data; }
 
-namespace probabilistic {
+ZEEK_FORWARD_DECLARE_NAMESPACED(BitVector, zeek, probabilistic, detail);
 
-class BitVector;
+namespace zeek::probabilistic::detail {
 
 /**
  * A vector of counters, each of which has a fixed number of bits.
@@ -154,4 +156,8 @@ private:
 	size_t width;
 };
 
+} // namespace zeek::probabilistic::detail
+
+namespace probabilistic {
+	using CounterVector [[deprecated("Remove in v4.1. Use zeek::probabilisitc::detail::CounterVector.")]] = zeek::probabilistic::detail::CounterVector;
 }
diff --git a/src/probabilistic/Hasher.cc b/src/probabilistic/Hasher.cc
index f24ddecca0..58ad36944e 100644
--- a/src/probabilistic/Hasher.cc
+++ b/src/probabilistic/Hasher.cc
@@ -13,7 +13,7 @@
 
 #include <broker/data.hh>
 
-using namespace probabilistic;
+namespace zeek::probabilistic::detail {
 
 Hasher::seed_t Hasher::MakeSeed(const void* data, size_t size)
 	{
@@ -178,3 +178,5 @@ bool DoubleHasher::Equals(const Hasher* other) const
 	const DoubleHasher* o = static_cast<const DoubleHasher*>(other);
 	return h1 == o->h1 && h2 == o->h2;
 	}
+
+} // namespace zeek::probabilistic::detail
diff --git a/src/probabilistic/Hasher.h b/src/probabilistic/Hasher.h
index 8154a0dcb2..12cc36bd73 100644
--- a/src/probabilistic/Hasher.h
+++ b/src/probabilistic/Hasher.h
@@ -10,7 +10,7 @@
 
 namespace broker { class data; }
 
-namespace probabilistic {
+namespace zeek::probabilistic::detail {
 
 /** Types of derived Hasher classes. */
 enum HasherType { Default, Double };
@@ -257,4 +257,17 @@ private:
 	UHF h2;
 };
 
+} // namespace zeek::probabilistic::detail
+
+namespace probabilistic {
+
+	using HasherType [[deprecated("Remove in v4.1. Use zeek::probabilistic::detail::HasherType.")]] = zeek::probabilistic::detail::HasherType;
+	constexpr auto Default [[deprecated("Remove in v4.1. Use zeek::probabilistic::detail::Default.")]] = zeek::probabilistic::detail::Default;
+	constexpr auto Double [[deprecated("Remove in v4.1. Use zeek::probabilistic::detail::Double.")]] = zeek::probabilistic::detail::Double;
+
+	using Hasher [[deprecated("Remove in v4.1. Use zeek::probabilistic::detail::Hasher.")]] = zeek::probabilistic::detail::Hasher;
+	using UHF [[deprecated("Remove in v4.1. Use zeek::probabilistic::detail::UHF.")]] = zeek::probabilistic::detail::UHF;
+	using DefaultHasher [[deprecated("Remove in v4.1. Use zeek::probabilistic::detail::DefaultHasher.")]] = zeek::probabilistic::detail::DefaultHasher;
+	using DoubleHasher [[deprecated("Remove in v4.1. Use zeek::probabilistic::detail::DoubleHasher.")]] = zeek::probabilistic::detail::DoubleHasher;
+
 }
diff --git a/src/probabilistic/Topk.cc b/src/probabilistic/Topk.cc
index 06a1543209..a1b14bad00 100644
--- a/src/probabilistic/Topk.cc
+++ b/src/probabilistic/Topk.cc
@@ -9,7 +9,7 @@
 #include "Reporter.h"
 #include "Dict.h"
 
-namespace probabilistic {
+namespace zeek::probabilistic::detail {
 
 static void topk_element_hash_delete_func(void* val)
 	{
@@ -519,4 +519,5 @@ bool TopkVal::DoUnserialize(const broker::data& data)
 	assert(i == numElements);
 	return true;
 	}
-}
+
+} // namespace zeek::probabilistic::detail
diff --git a/src/probabilistic/Topk.h b/src/probabilistic/Topk.h
index f776eada29..bab6bfeb47 100644
--- a/src/probabilistic/Topk.h
+++ b/src/probabilistic/Topk.h
@@ -11,7 +11,7 @@
 
 ZEEK_FORWARD_DECLARE_NAMESPACED(CompositeHash, zeek::detail);
 
-namespace probabilistic {
+namespace zeek::probabilistic::detail {
 
 struct Element;
 
@@ -172,4 +172,10 @@ private:
 	bool pruned; // was this data structure pruned?
 };
 
-};
+} // namespace zeek::probabilistic::detail
+
+namespace probabilistic {
+	using Element [[deprecated("Remove in v4.1. Use zeek::probabilistic::detail::Element.")]] = zeek::probabilistic::detail::Element;
+	using Bucket [[deprecated("Remove in v4.1. Use zeek::probabilistic::detail::Bucket.")]] = zeek::probabilistic::detail::Bucket;
+	using TopkVal [[deprecated("Remove in v4.1. Use zeek::probabilistic::detail::TopkVal.")]] = zeek::probabilistic::detail::TopkVal;
+}
diff --git a/src/probabilistic/bloom-filter.bif b/src/probabilistic/bloom-filter.bif
index 1ca5a4fdbb..c5fb31f9b8 100644
--- a/src/probabilistic/bloom-filter.bif
+++ b/src/probabilistic/bloom-filter.bif
@@ -40,13 +40,13 @@ function bloomfilter_basic_init%(fp: double, capacity: count,
 		return nullptr;
 		}
 
-	size_t cells = BasicBloomFilter::M(fp, capacity);
-	size_t optimal_k = BasicBloomFilter::K(cells, capacity);
-	Hasher::seed_t seed = Hasher::MakeSeed(name->Len() > 0 ? name->Bytes() : 0,
-                                 name->Len());
-	const Hasher* h = new DoubleHasher(optimal_k, seed);
+	size_t cells = zeek::probabilistic::BasicBloomFilter::M(fp, capacity);
+	size_t optimal_k = zeek::probabilistic::BasicBloomFilter::K(cells, capacity);
+	zeek::probabilistic::detail::Hasher::seed_t seed =
+		zeek::probabilistic::detail::Hasher::MakeSeed(name->Len() > 0 ? name->Bytes() : 0, name->Len());
+	const zeek::probabilistic::detail::Hasher* h = new zeek::probabilistic::detail::DoubleHasher(optimal_k, seed);
 
-	return zeek::make_intrusive<zeek::BloomFilterVal>(new BasicBloomFilter(h, cells));
+	return zeek::make_intrusive<zeek::BloomFilterVal>(new zeek::probabilistic::BasicBloomFilter(h, cells));
 	%}
 
 ## Creates a basic Bloom filter. This function serves as a low-level
@@ -82,11 +82,11 @@ function bloomfilter_basic_init2%(k: count, cells: count,
 		return nullptr;
 		}
 
-	Hasher::seed_t seed = Hasher::MakeSeed(name->Len() > 0 ? name->Bytes() : 0,
-				       name->Len());
-	const Hasher* h = new DoubleHasher(k, seed);
+	zeek::probabilistic::detail::Hasher::seed_t seed =
+		zeek::probabilistic::detail::Hasher::MakeSeed(name->Len() > 0 ? name->Bytes() : 0, name->Len());
+	const zeek::probabilistic::detail::Hasher* h = new zeek::probabilistic::detail::DoubleHasher(k, seed);
 
-	return zeek::make_intrusive<zeek::BloomFilterVal>(new BasicBloomFilter(h, cells));
+	return zeek::make_intrusive<zeek::BloomFilterVal>(new zeek::probabilistic::BasicBloomFilter(h, cells));
 	%}
 
 ## Creates a counting Bloom filter.
@@ -121,16 +121,16 @@ function bloomfilter_counting_init%(k: count, cells: count, max: count,
 		return nullptr;
 		}
 
-	Hasher::seed_t seed = Hasher::MakeSeed(name->Len() > 0 ? name->Bytes() : 0,
-				       name->Len());
+	zeek::probabilistic::detail::Hasher::seed_t seed =
+		zeek::probabilistic::detail::Hasher::MakeSeed(name->Len() > 0 ? name->Bytes() : 0, name->Len());
 
-	const Hasher* h = new DefaultHasher(k, seed);
+	const zeek::probabilistic::detail::Hasher* h = new zeek::probabilistic::detail::DefaultHasher(k, seed);
 
 	uint16_t width = 1;
 	while ( max >>= 1 )
 		++width;
 
-	return zeek::make_intrusive<zeek::BloomFilterVal>(new CountingBloomFilter(h, cells, width));
+	return zeek::make_intrusive<zeek::BloomFilterVal>(new zeek::probabilistic::CountingBloomFilter(h, cells, width));
 	%}
 
 ## Adds an element to a Bloom filter.
@@ -144,7 +144,7 @@ function bloomfilter_counting_init%(k: count, cells: count, max: count,
 ##    bloomfilter_merge
 function bloomfilter_add%(bf: opaque of bloomfilter, x: any%): any
 	%{
-	BloomFilterVal* bfv = static_cast<BloomFilterVal*>(bf);
+	auto* bfv = static_cast<BloomFilterVal*>(bf);
 
 	if ( ! bfv->Type() && ! bfv->Typify(x->GetType()) )
 		reporter->Error("failed to set Bloom filter type");
@@ -171,7 +171,7 @@ function bloomfilter_add%(bf: opaque of bloomfilter, x: any%): any
 ##    bloomfilter_merge
 function bloomfilter_lookup%(bf: opaque of bloomfilter, x: any%): count
 	%{
-	const BloomFilterVal* bfv = static_cast<const BloomFilterVal*>(bf);
+	const auto* bfv = static_cast<const BloomFilterVal*>(bf);
 
 	if ( ! bfv->Type() )
 		return zeek::val_mgr->Count(0);
@@ -196,7 +196,7 @@ function bloomfilter_lookup%(bf: opaque of bloomfilter, x: any%): count
 ##    bloomfilter_merge
 function bloomfilter_clear%(bf: opaque of bloomfilter%): any
 	%{
-	BloomFilterVal* bfv = static_cast<BloomFilterVal*>(bf);
+	auto* bfv = static_cast<BloomFilterVal*>(bf);
 
 	if ( bfv->Type() ) // Untyped Bloom filters are already empty.
 		bfv->Clear();
@@ -222,8 +222,8 @@ function bloomfilter_clear%(bf: opaque of bloomfilter%): any
 function bloomfilter_merge%(bf1: opaque of bloomfilter,
 			    bf2: opaque of bloomfilter%): opaque of bloomfilter
 	%{
-	const BloomFilterVal* bfv1 = static_cast<const BloomFilterVal*>(bf1);
-	const BloomFilterVal* bfv2 = static_cast<const BloomFilterVal*>(bf2);
+	const auto* bfv1 = static_cast<const BloomFilterVal*>(bf1);
+	const auto* bfv2 = static_cast<const BloomFilterVal*>(bf2);
 
 	if ( bfv1->Type() && // any one 0 is ok here
 	     bfv2->Type() &&
@@ -244,6 +244,6 @@ function bloomfilter_merge%(bf1: opaque of bloomfilter,
 ## Returns: a string with a representation of a Bloom filter's internal state.
 function bloomfilter_internal_state%(bf: opaque of bloomfilter%): string
 	%{
-	BloomFilterVal* bfv = static_cast<BloomFilterVal*>(bf);
+	auto* bfv = static_cast<BloomFilterVal*>(bf);
 	return zeek::make_intrusive<zeek::StringVal>(bfv->InternalState());
 	%}
diff --git a/src/probabilistic/cardinality-counter.bif b/src/probabilistic/cardinality-counter.bif
index 8069003c2b..da1fd4baf3 100644
--- a/src/probabilistic/cardinality-counter.bif
+++ b/src/probabilistic/cardinality-counter.bif
@@ -22,7 +22,7 @@ module GLOBAL;
 ##    hll_cardinality_copy
 function hll_cardinality_init%(err: double, confidence: double%): opaque of cardinality
 	%{
-	CardinalityCounter* c = new CardinalityCounter(err, confidence);
+	auto* c = new zeek::probabilistic::detail::CardinalityCounter(err, confidence);
 	auto cv = zeek::make_intrusive<zeek::CardinalityVal>(c);
 
 	return cv;
@@ -40,7 +40,7 @@ function hll_cardinality_init%(err: double, confidence: double%): opaque of card
 ##    hll_cardinality_init hll_cardinality_copy
 function hll_cardinality_add%(handle: opaque of cardinality, elem: any%): bool
 	%{
-	CardinalityVal* cv = static_cast<CardinalityVal*>(handle);
+	auto* cv = static_cast<CardinalityVal*>(handle);
 
 	if ( ! cv->Type() && ! cv->Typify(elem->GetType()) )
 		{
@@ -73,8 +73,8 @@ function hll_cardinality_add%(handle: opaque of cardinality, elem: any%): bool
 ##    hll_cardinality_init hll_cardinality_copy
 function hll_cardinality_merge_into%(handle1: opaque of cardinality, handle2: opaque of cardinality%): bool
 	%{
-	CardinalityVal* v1 = static_cast<CardinalityVal*>(handle1);
-	CardinalityVal* v2 = static_cast<CardinalityVal*>(handle2);
+	auto* v1 = static_cast<CardinalityVal*>(handle1);
+	auto* v2 = static_cast<CardinalityVal*>(handle2);
 
 	if ( (v1->Type() != v2->Type()) && // both 0 is ok
 	     (v1->Type() != nullptr) && // any one 0 also is ok
@@ -85,8 +85,8 @@ function hll_cardinality_merge_into%(handle1: opaque of cardinality, handle2: op
 		return zeek::val_mgr->False();
 		}
 
-	CardinalityCounter* h1 = v1->Get();
-	CardinalityCounter* h2 = v2->Get();
+	zeek::probabilistic::detail::CardinalityCounter* h1 = v1->Get();
+	zeek::probabilistic::detail::CardinalityCounter* h2 = v2->Get();
 
 	bool res = h1->Merge(h2);
 	if ( ! res )
@@ -108,8 +108,8 @@ function hll_cardinality_merge_into%(handle1: opaque of cardinality, handle2: op
 ##    hll_cardinality_init hll_cardinality_copy
 function hll_cardinality_estimate%(handle: opaque of cardinality%): double
 	%{
-	CardinalityVal* cv = static_cast<CardinalityVal*>(handle);
-	CardinalityCounter* h = cv->Get();
+	auto* cv = static_cast<CardinalityVal*>(handle);
+	zeek::probabilistic::detail::CardinalityCounter* h = cv->Get();
 
 	double estimate = h->Size();
 
@@ -126,9 +126,9 @@ function hll_cardinality_estimate%(handle: opaque of cardinality%): double
 ##    hll_cardinality_init
 function hll_cardinality_copy%(handle: opaque of cardinality%): opaque of cardinality
 	%{
-	CardinalityVal* cv = static_cast<CardinalityVal*>(handle);
-	CardinalityCounter* h = cv->Get();
-	CardinalityCounter* h2 = new CardinalityCounter(*h);
+	auto* cv = static_cast<CardinalityVal*>(handle);
+	zeek::probabilistic::detail::CardinalityCounter* h = cv->Get();
+	auto* h2 = new zeek::probabilistic::detail::CardinalityCounter(*h);
 	auto out = zeek::make_intrusive<zeek::CardinalityVal>(h2);
 
 	return out;
diff --git a/src/probabilistic/top-k.bif b/src/probabilistic/top-k.bif
index 64faeaa31b..9695dcf26e 100644
--- a/src/probabilistic/top-k.bif
+++ b/src/probabilistic/top-k.bif
@@ -14,7 +14,7 @@
 ##    topk_size topk_sum topk_merge topk_merge_prune
 function topk_init%(size: count%): opaque of topk
 	%{
-	auto v = zeek::make_intrusive<probabilistic::TopkVal>(size);
+	auto v = zeek::make_intrusive<zeek::probabilistic::detail::TopkVal>(size);
 	return v;
 	%}
 
@@ -33,7 +33,7 @@ function topk_init%(size: count%): opaque of topk
 function topk_add%(handle: opaque of topk, value: any%): any
 	%{
 	assert(handle);
-	probabilistic::TopkVal* h = (probabilistic::TopkVal*) handle;
+	auto* h = (zeek::probabilistic::detail::TopkVal*) handle;
 	h->Encountered({zeek::NewRef{}, value});
 
 	return nullptr;
@@ -52,7 +52,7 @@ function topk_add%(handle: opaque of topk, value: any%): any
 function topk_get_top%(handle: opaque of topk, k: count%): any_vec
 	%{
 	assert(handle);
-	probabilistic::TopkVal* h = (probabilistic::TopkVal*) handle;
+	auto* h = (zeek::probabilistic::detail::TopkVal*) handle;
 	return h->GetTopK(k);
 	%}
 
@@ -73,7 +73,7 @@ function topk_get_top%(handle: opaque of topk, k: count%): any_vec
 function topk_count%(handle: opaque of topk, value: any%): count
 	%{
 	assert(handle);
-	probabilistic::TopkVal* h = (probabilistic::TopkVal*) handle;
+	auto* h = (zeek::probabilistic::detail::TopkVal*) handle;
 	return zeek::val_mgr->Count(h->GetCount(value));
 	%}
 
@@ -93,7 +93,7 @@ function topk_count%(handle: opaque of topk, value: any%): count
 function topk_epsilon%(handle: opaque of topk, value: any%): count
 	%{
 	assert(handle);
-	probabilistic::TopkVal* h = (probabilistic::TopkVal*) handle;
+	auto* h = (zeek::probabilistic::detail::TopkVal*) handle;
 	return zeek::val_mgr->Count(h->GetEpsilon(value));
 	%}
 
@@ -112,7 +112,7 @@ function topk_epsilon%(handle: opaque of topk, value: any%): count
 function topk_size%(handle: opaque of topk%): count
 	%{
 	assert(handle);
-	probabilistic::TopkVal* h = (probabilistic::TopkVal*) handle;
+	auto* h = (zeek::probabilistic::detail::TopkVal*) handle;
 	return zeek::val_mgr->Count(h->GetSize());
 	%}
 
@@ -132,7 +132,7 @@ function topk_size%(handle: opaque of topk%): count
 function topk_sum%(handle: opaque of topk%): count
 	%{
 	assert(handle);
-	probabilistic::TopkVal* h = (probabilistic::TopkVal*) handle;
+	auto* h = (zeek::probabilistic::detail::TopkVal*) handle;
 	return zeek::val_mgr->Count(h->GetSum());
 	%}
 
@@ -152,8 +152,8 @@ function topk_merge%(handle1: opaque of topk, handle2: opaque of topk%): any
 	assert(handle1);
 	assert(handle2);
 
-	probabilistic::TopkVal* h1 = (probabilistic::TopkVal*) handle1;
-	probabilistic::TopkVal* h2 = (probabilistic::TopkVal*) handle2;
+	auto* h1 = (zeek::probabilistic::detail::TopkVal*) handle1;
+	auto* h2 = (zeek::probabilistic::detail::TopkVal*) handle2;
 
 	h1->Merge(h2);
 
@@ -178,8 +178,8 @@ function topk_merge_prune%(handle1: opaque of topk, handle2: opaque of topk%): a
 	assert(handle1);
 	assert(handle2);
 
-	probabilistic::TopkVal* h1 = (probabilistic::TopkVal*) handle1;
-	probabilistic::TopkVal* h2 = (probabilistic::TopkVal*) handle2;
+	auto* h1 = (zeek::probabilistic::detail::TopkVal*) handle1;
+	auto* h2 = (zeek::probabilistic::detail::TopkVal*) handle2;
 
 	h1->Merge(h2, true);